“My VAAI is Better Than Yours” – The file side of things

7 02 2012

EMC VNXI have to admit it. I stole, or rather “borrowed”, part of this title from a blog post of a colleague of mine, Erik Zandboer. He just now published a post on the mindset behind VAAI, and what the actual effect is on the array itself, and on your vSphere infrastructure.

VAAI was already available in vSphere 4.1, and with the switch to vSphere 5 some new features were introduced, which means that as of this release, we now have the following situation:

Block:  File: 
HW accelerated Zeroing  NFS – Full Copy 
HW accelerated Copy  NFS – Extended Statistics 
HW accelerated Locking  NFS – Space Reservation 

Some folks will say that I left out Thin Provision Stun, which is true. And while it does help to resolve some issues, I left it out because I don’t really view it as a hardware offload, which is what I’m trying to focus on.

I took the hardware in our lab, – a EMC VNX 5300 -, for a spin in our vSphere 5 setup to show the same thing as Erik showed in his blog, but instead showing off some of the File / NFS accelerations.

To get the VNX to actually support NAS VAAI offloading and get the result you expected, you need to meet the following prerequisites:

  • vSphere 5 – You need vSphere 5 installed with an Enterprise or Enterprise Plus license
  • VNX OE for File 7.0.35.x – You need your VNX Operating Environment for File to be at least at version VNX OE 7.0.35.x or newer
  • NFSv3 – The offloads only work on NFSv3-based datastores

If all those prerequisites are met, you should normally be able to go in to your vSphere Client and see Hardware Acceleration as Supported:

You could also enable SSH for your ESXi host, – do this by going to the individual host, click on the “Configuration” tab, select “Security Profile” and start the SSH service -, and check the support from the command line. For block devices you could enter the following command:

esxcli storage core device vaai status getand get back a result that shows you the NAAID, the VAAI plugin name, and the primitives with their support state. By using the following command:
esxcli storage core device list you get a similar output, but again this only works for block devices, and won’t really help you when checking the support for NFS. I haven’t found any way so far to get a reliable statement back via SSH, but I’ll try to continue looking and update this post if I find something.

In case of the VNX, we can actually check on the array itself to see if we are using the primitives, so I’m actually showing you the output from the array itself, using the following command on the VNX:

server_stats server_2 -monitor nfs.v3.vstorage -type accu -i 1
First off, I went back in to my ESXi host and went in to the NFSv3 datastore that was hosting my virtual machine. In this case, a Windows 2008 server, running an SAP Enterprise Portal, and I used the vmkfstools to create a clone:

vmkfstools -i GI-C-SAP-EPBW.vmdk CLONE-GI-C-SAP-EPBW.vmdkand I set off a snap using a similar command:
vmkfstools -i GI-C-SAP-EPBW.vmdk CLONE-GI-C-SAP-EPBW.vmdk. All the while, I had the VNX command that I posted before running in a different window. The output from the VNX was showing that we are actually using the VAAI NFS offloading functions:

server_2 NFS VAAI op VAAI Op Calls VAAI Op Total uSecs VAAI VAAI Op
Timestamp Op Max Average
uSecs uSec/Op
09:07:14
09:07:15
09:07:16
09:07:17
09:07:18 vaaiFastClone 1 0 0 0
vaaiVxAttrs 3 0 1 0
vaaiRegister 5 0 0 0
09:07:19
.......
09:08:27 vaaiOffloadStatus 1 0 0 0
vaaiVxAttrs 7 1 1 0
vaaiRegister 10 0 0 0
09:08:28
09:08:29
09:08:30
09:08:31
09:08:32 vaaiOffloadStatus 2 0 0 0
server_2 NFS VAAI op VAAI Op Calls VAAI Op Total uSecs VAAI VAAI Op
Summary Op Max Average
uSecs uSec/Op
Minimum vaaiFullClone 0 0 83308 -
vaaiFastClone 0 0 0 0
vaaiOffloadStatus 0 0 0 0
vaaiOffloadAbort 0 0 0 -
vaaiVxAttrs 0 0 1 0
vaaiReserveSpace 0 0 0 -
vaaiRegister 0 0 0 0
Average vaaiFullClone 0 0 83308 -
vaaiFastClone 1 0 0 0
vaaiOffloadStatus 0 0 0 0
vaaiOffloadAbort 0 0 0 -
vaaiVxAttrs 3 0 1 0
vaaiReserveSpace 0 0 0 -
vaaiRegister 5 0 0 0
Maximum vaaiFullClone 0 0 83308 -
vaaiFastClone 1 0 0 0
vaaiOffloadStatus 2 0 0 0
vaaiOffloadAbort 0 0 0 -
vaaiVxAttrs 7 1 1 0
vaaiReserveSpace 0 0 0 -
vaaiRegister 10 0 0 0
(sorry for the formatting, I couldn’t get it to show the way it should).

Once the files are created, use a:
vmkfstools --extendedstat GI-C-SAP-EPBW.vmdk on the source file, or on the snap or clone to actually display the extended statistics. The “Capacity bytes” show the allocated space for the virtual disk, the “Used bytes” displays the blocks used for the virtual disk which in case of our snapshot is the fast clone and it’s parent. The “Unshared bytes” displays the usage of the actual fast clone itself without the parent.

I should point out that the offload did speed up my full clone operation, but it was “only” in the range of 20%. That isn’t a great deal, but using both esxtop and the vSphere Client performance graphs showed that the ESXi server was busy doing what it is supposed to do: virtualizing my resources! And that’s the most important thing, isn’t it?


Comments : 1 Comment »
Tags: , ,
Categories : EMC, Storage, VAAI, VMware, VNX, vSphere

Problem with the EMC Isilon Storage Replication Adapter

9 01 2012

VMware vCenter SRMA lot of folks out there use the VMware vCenter SRM to create and manage disaster recovery scenarios for their virtualized environments.

Besides having a button to click to fail over (parts of) your environment to a different site, it has one benefit: It forces you to think about your systems. You need to consider which systems are vital to your infrastructure, and you need to be aware of dependencies that you may have in your environment. There are numerous other things that SRM can help with, but that’s not what I wanted to highlight here.

A couple of days ago, I was at the VMware office in Munich, and was helping setting up a SRM 5.0 demo that would serve as a hands-on lab for people interested in SRM. The base of this SRM installation is a virtualized Isilon cluster, that offers the ability to easily provision storage, and offers replication between sites (a quick video overview by my colleague Nick Weaver can be found ).

While setting up the Isilon SRA which you can download from the VMware website, I ran in to a problem. When you download and extract the actual SRA, you’ll get a bunch of PDF files, and two executables. One is the installer for the actual storage replication adapter. It’s called “EMCIsilonSRASetup_1_0.exe”, and you need a current Java development kit to get that one running, but it should install correctly.

The second file is called “IsilonReplicationHelperSetup.exe”, and this is used to configure the SRA before using it in SRM. Now, when starting this helper, both me and Jase McCarty have seen errors that refer to a missing Java class (com.izforge.izpack.installer.Installer), for a program called IzPack which was used to create the installer. After extracting the actual executable, it seemed like some classes/libraries were missing from it.

I’ve been in touch with Isilon support after running in to the error, and after checking with them, they gave me an MD5 hash of a working copy of the IsilonReplicationHelperSetup.exe, which is:
416535bc1c7d7f133037af04b5502e3b However, MD5 for the executable that I got was:
4342E880A99EE2ED6DA1205F1018233DWhich obviously is different. The MD5 of the downloaded file, and the MD5 that VMware shows for the actual zip that contains the SRA matched up though.

So, I’m putting this post out there as a word of warning. It seems like one of the Isilon SRA files on the VMware website is non-functional. Should anybody out there see this, make sure to contact Isilon support and reference case 00169080, which is my case number.

I’m still working with the Isilon support to see what the next steps are going to be, and I’m sure this is going to be resolved soon enough, but I wanted to put this information out there for you in the meantime, to avoid people having to go through the same process as I did. It might save some folks a bit of time. And I’ll make sure I update this post when I get a solution from the Isilon support team.

Update – January 16th 2012:

While I’m still working with the Isilon support group to get everything sorted out, I did get a version of the IsilonReplicationHelperSetup Java archive that seems to be working. Now, I’m sharing this with you all while we try to get things resolved, and to get the working download on the VMware site, but I need to add a large disclaimer:

This file is not officially supported by EMC and/or Isilon, and while this file worked for me, your mileage may vary, and I would recommend that you do not use this file in a production environment! The file might work in a test environment, but please refrain from using it in a productive environment. Use the official files from the VMware download site, or create a case with Isilon and/or VMware support!

Now, to help you verify this file, the MD5 for the Java archive is:
FFAC907E70FD0BFC73076793B9D5FCB4and you can get the file here.


Comments : Leave a Comment »
Tags: , , , , , ,
Categories : Isilon, SRM, Storage, Virtualization, VMware

VMAX VSA: IT’S ALIVE!!!!!!!!!!!!!!!!

31 08 2011

So folks, here’s a shameless copy of a blog post from one of the guys on my team. Dave was just brilliant and actually created a virtual storage appliance of the EMC VMAX. I think that’s downright awesome, and I wanted to help him get attention for what he did, so I asked him if I could copy his blog post, which is what you will find here:

young_frankenstein_doc_small

 

As the title suggests there is indeed a Symmetrix VMAX VSA. I have been working on this project since shortly after EMC World. As I look back through my emails, I received the code on 6/3/11 and I have been working on it in almost all of my free time since then.

Now finally it will make its public debut this week at VMworld 2011 as part of the EMC Interactive Demo booth on the show floor. As part of its grand unveiling I thought I would tell you a little about what makes it work.

Now to make a few things clear up front, this is a science project, I cannot distribute it, it does “work”. As part of the lab (I will publish the guide) the student actually provisions an iSCSI disk from the VSA to a ESXi 5.0 host.

One of the first things I noticed with the code when trying to virtualize it. It’s HUGE. There are 2 parts to the VSA.

1. The Service Processor (SP). In a physical VMAX this is the 1U server that is racked in the system bay. It has a special image of Windows XP and contains all of the proprietary software used to manage a VMAX. If you own a VMAX this is what you will see EMC field service personnel using when they come to work on your system. This is NOT accessible by a end-user as it requires special RSA credentials that change weekly. (one reason we can’t distribute it). Its specs are 2vCPU and 2GB of RAM and about 10GB of disk space.

2. Enginuity. This is the Operating Environment of the Symmetrix. For the purposes of this VSA it runs in a SuSE Enterprise Linux 11VM. One of the big deals with the VMAX was that Enginuity was ported from a PowerPC CPU to a Intel x86 based architecture. Without this change this VSA would never exist. Now this VM is big, so big as a matter of fact i had to use a RC build of vSphere 5 in order to even get it to work. I was finally able to scale it down a bit, but at one point it was using 32 vCPU’s 92GB of RAM and about 250GB of disk space.

Obviously one of the challenges for using this in a lab is that I needed it to use fewer resources. In the beginning this VMAX was a Single Engine model, which means it had 16 “slices” running. Each director has 4 DA (backend) directors, and 4 FA (front end) directors. I quickly found this was the biggest reason i needed so much memory and CPU. After working with one developer Chakib, who totally rocks by the way. We were able to scale this down to 1 FA and 1 DA per director. One interesting side note, when I was going down this path I asked Chakib what kind of VM he was using to test this. His reply was, “I am not using this in a VM, I have a physical Linux box with 200GB of RAM”. So I clearly had some work to do. But in its current state it uses 8 vCPU and “ONLY” 48GB of RAM. Which is still pretty darn big, but a lot better than it was when we started.

The networking requirements are pretty simple, the SP needs 1 Public NIC so that we can use its management tools. 2 Internal NICs which is used for internal communication to the directors. In our case that’s the Linux VM. The Linux VM needed the 2 internal NICs and 1 NIC to present an iSCSI target to. Then we put out ESXi host’s VMkernel NIC on the same vSwitch so it can use the iSCSI target provided by the VSA.

So that’s all great you say, but what actually works? That’s a good question.

What works is using Standard Devices, and very small ones today. One of the things I was told when I was given the code was that this WON’T and CAN’T do any I/O. Which obviously proved to be a bit of an issue. Chakib really worked his butt of to get me something that does I/O. So this is not like the Celerra UBER VSA by @lynxbat, where you can run a VM off of it. We hope we can do that one day. Thin Pools work to the extent you can create them, and put devices in a pool, but when you present it to a host it will not work. This kept me from using the VSI SPM plugin for vSphere as part of my lab, hey we always have next year! The really neat part to me is that the internal tools (SymmWin) that run on the SP fully work. It’s like having an actually VMAX, but without all the fuss of getting a few 50A power drops. As an ex-customer this to me is the coolest part, I got to put on my own BIN files, use Inlines (internal tool used to directly talk to the hardware). As a total nerd this thing is a dream come true.

So what’s next?

Well a lot of that depends on YOU! Since this is a total science project we need to show those in Symmetrix Engineering this is worth putting their time and money into. I need everyone here at VMworld this week to come try this thing, give me feedback, leave comments here, and if you aren’t at the show, express your desire for us to continue working on it. If no one is interested this will ultimately die on the vine. Please fill out this form so we can show how many of you all would like to see this project continue.

I have to give special thanks to Chad Sakac (@sakacc), Chris Horn (@horn_Chris) for getting me involved in this project and letting me run with it. Also all of the support they gave me during this process.

Here is a link to the lab guide being used this week at VMworld. Take a look and let me know what you think!

VMAX Lab Guide

Big thanks to Matt Cowger (@mcowger), Scott Lowe (@scott_lowe), and Tee Glasgow (@teeglasgow) for their help with the lab guide. Also to Rick Scherer (@rick_vmwaretips) for the blog help


Comments : Leave a Comment »
Tags: , , ,
Categories : EMC, Storage, V-MAX, Virtualization, VMware

Post convention melancholy

14 05 2011

I’m sitting on board of a delayed Airbus A320 from Las Vegas to Chicago while I’m writing up this small post.

I left for Las Vegas must over a week ago to help set up gear for EMC World, and my week has been amazing. After landing inVegas, I met up with some of the guys, went to dinner and to bet, just to be wide awake at two in the morning due to jet lag. Ain’t that just the way it goes?

Anyway, after attending some conference calls, the rest of the team was up and that meant it was time to get started setting things up. Part of it was wrapping up the guides that were created for the labs, and converting them to a format that was suitable for the lab guide reader that was created by fellow vSpecialist Nick Weaver.

Part of it was also to get the backup system up and running on site, because even though we ran the entire vLabs off of the infrastructure located on the other side of the USA, we needed a backup system that would be able to support the labs in case of issues. And one of the first challenges was to actually get the back hardware to the convention center, and actually getting the truck to the right spot to offload the hardware wasn’t as easy as it sounds. Not to mention the fact that it’s hard to work when people actually relocate you from room to room on what seemed to be an hourly basis.

But, all worked out in the end. We were able to get everything loaded and working, and actually started setting up shop in the vLabs area I the convention center. 200 WYSE consoles, custom written lab management software, almost 20 different labs to pick from, and a team of well over 25 folks helping out assured that the vLabs were a good experience.

Did it all run smoothly? No, not all of the time. If you eat your own dog food, want to be bleeding edge and run your service in the cloud, you are bound to run in to some glitches and hiccups. Think of things like firewalls that get in your way, switches not cooperating, or even something like a simulator that tends to crash more than it works (I’m looking at you RecoverPoint 3.4 Sim….). Then, there’s also the fact that this was a first for us in such an environment and at such a scale.

And even with those things, we managed to do an incredible job. We had a great team on site that pulled all nighters to get our environment up and running. Some of us have been living off of about 3 hours of sleep per night, but we still managed to provision over 3000 VMs (exact numbers to be published soon).

And besides the hard work we also had a lot of fun. We got to play craps with two Elvi, perform a pit stop for Wayne and Garth (errr, Chad and Wade), and the random Hangover quotes on our lab headsets were always good for a chuckle.

And now, I’m flying back home and am feeling somewhat melancholic. It’s been a hell of a ride, and coming down from the chaos, or not getting to hang out with my colleagues until I see them again the next time is sort of a strange feeling. It’s like saying goodbye to a dear friend that is leaving for a while, and although you have some very good memories, it leaves you with a sort of funny feeling.

So, for now I want to thank all of the guys that made this week an incredible experience. Folks like Aaron, Erin, Nick, Dave, Rick, Travers, Fred, Tommy, JT and Heather. And of course all of the others that I won’t all name here right now. Thanks guys!

And as the king said it: Viva Las Vegas!


Comments : 1 Comment »
Tags:
Categories : EMC, General, Storage, Virtualization

What’s new in EMC Clariion CX4 FLARE 30

20 10 2010

CLARiiON CX4 UltraFlex I/O module - Copyright: EMC Corporation.A little while back, EMC released a new version of it’s CLARiiON Fibre Logic Array Runtime Environment, or in short “FLARE” operating environment. This release brings us to version 04.30 and again has some enhancements that might interest you, so once more here’s a short overview of what this update packs:

Let’s start off with some basics. Along with this update you will find updated firmware versions for the following:

    Enclosure: DAE2		- FRUMon: 5.10
Enclosure: DAE2-ATA	- FRUMon: 1.99
Enclosure: DAE2P	- FRUMon: 6.71
Enclosure: DAE3P	- FRUMon: 7.81

Major changes:

  • With version 04.30.000.5.507 you get support for FCoE. Prerequisite is using a 10 Gigabit Ethernet I/O module on CX4-120, CX4-240, CX4-480, and CX4-960 arrays.
  • SATA EFD support.
  • Following that point, you can now use Fibre Channel EFD and SATA EFD in the same DAE.
  • And, you can now also mix Fibre Channel and SATA EFDs in the same RAID group.
  • VMware vStorage API support in form of “vStorage full copy acceleration” (basically the array takes care of copying all the blocks, instead of sending everything to and from the application) and in form of “Compare and Swap” (an enhancement to the LUN locking mechanism).
  • Rebuild avoidance. This feature will change the routing of I/O to the service processor that still has access to all the drives in the RAID group. You do need write caching to be enabled if you want to be able to use this feature.
  • Virtual provisioning, basically EMC’s name for thin provisioning on the array.

There are some nice features in there, but for me personally the virtual provisioning, the FCoE support and the vStorage API support are the main ones.

One thing that caught my eye was in the section called limitations for FLARE version 04.30.000.5.507. In the release notes you will find the following statement:

Host attach support – Supported host attached systems are limited to the following operating systems: Windows, VMWare, and Linux

Which would mean that you have a problem when you are using something else like Solaris or HP-UX. I’m trying to get some confirmation, and I’ll update this post as soon as I have more info.

Update

The statement has changed in the meantime:

Host attach support – Supported hosts that can be attached over an FCoE connection are limited to the following operating systems: Windows, VMWare, and Linux

Which means that this is just related to FCoE connected hosts.

After some feedback on Twitter from among others Andrew Sharrock, I’d thought it might be wise to talk a few sentences about the Virtual Provisioning feature.

In short, Virtual Provisioning was already introduced with FLARE 28. Problem was that at the time, you could only use the feature with thin pools. Basically, with this update, you also get support for a newer version of the feature. Things that were added are:

  • Thick LUNs
  • LUN expand and shrink
  • Tiering preference (storage allocation from pools with mixed drives and different performance characteristics)
  • Per-tier tracking support of pool usage
  • RAID 1/0 support for pools
  • Increased limits for drive usage in pools

Comments : 1 Comment »
Tags: , , , , ,
Categories : Clariion, CX4, EMC, FLARE, Storage

It’s all about change and passion

28 06 2010

Some of you who read the title of this post will already have a hunch what this is all about. Heraclitus seems to be the person who first stated:

Nothing endures but change.

And I can only agree with that. I remember reading a post from Nick Weaver about an important change in his professional life, and I love this quote:

By taking this position I am intentionally moving myself from the top man on the totem pole to the lowest man on the rung.

And I think that most people who have read Nick’s blog know that this wasn’t entirely the truth, especially when looking what he was able to do until now.

Well, Nick can be assured now. There’s actually on person on the team that is “lower on the rung”. That person would be me.

Time for a change!

I am joining EMC and taking on the role of vSpecialist, or as my new contract says “Technical Consultant VCE”.

I am also going to be leaving my comfort zone and leave a team of people behind that have been great to work with. I have been working at SAP for seven years now, and the choice to leave wasn’t easy. I was lucky enough to have worked with a multitude of technologies in an environment that was high paced and stressful, but very rewarding, and I want to thank all of my colleagues for making the journey interesting! Even so, it’s time for me to make a change.

I was lucky enough to get to know several people who already work in a similar role, and if there’s one thing that distinguishes them in my mind, then it would be the passion they have for their job. This was actually the main reason for me to make the switch to EMC. It’s not about making big bucks, it’s not about being a mindless drone in the Evil Machine Company or drinking the Kool-Aid, it’s about getting a chance to work with people that share a passion and are experts at what they do. It’s about the chance to prove myself and perhaps one day joining their ranks as experts.

So, while I wrap things up here at SAP, if all goes well I will be joining the vSpecialist team on October 1st, and hopefully you will bear with me while I find my way going through this change, and I do hope you drop by every now and then to read some new posts from me.

See you on the other side!


Comments : 24 Comments »
Tags: , , , ,
Categories : Cisco, EMC, General, VMware

Shorts: Trouble with symapi_db.bin causing erratic behavior

26 05 2010

Usually when you are connected to a EMC Symmetrix array you will install the Solutions Enabler package on your system. Solutions Enabler is basically both a set of tools to help you manage your Symmetrix arrays, as well as an API. The Solutions Enabler basically creates a small database that displays what Symmetrix arrays are connected to the host you are running the software on, the so called SYMAPI database that you will find as a file on your system called “symapi_db.bin”.

Under a normal situation you will run a discover process to initially scan and fill the database with entries. To do that you can issue the command:

symcfg discover

This will start the scan operation, and depending on the amount of arrays and the configuration on those arrays you can plan anywhere from just under a minute for a scan up to several minutes. Once the file has been created you could try opening the file and searching for strings inside of the file, and you will find a lot of information about devices, device paths, disk IDs and lot’s more.

Now, in some situations after your array configuration has changed, it is useful to refresh the database file. Under normal circumstances this should all be easily done and without any issues.

However, in some cases your database file might be facing problems, without manifestation in any obvious ways. I have seen cases where new devices would simply not show up. Other examples are error messages about disks that can not be reached because of access control list errors.

If you happen to have some erratic behavior on one of your hosts, you might want to try one thing before creating a service request in Powerlink. You might want to try creating a copy of your database, removing it and then performing a new discover. Some steps to help you do just that:

  • Create a backup of your device and/or composite groups using the symdg/symcg commands.
  • Rename your old symapi_db.bin to something else.
  • Issue a “symcfg discover” to create a new symapi_db.bin
  • Import your device and/or composite groups from the backup file(s) you created.

This won’t help you in all situations, but it helped me solve several cases were we were seeing erratic behavior on our hosts, and it might do the trick for you.


Comments : 3 Comments »
Tags: , , , ,
Categories : EMC, Storage, Symmetrix

EMC VPLEX – Introduction and link overview

12 05 2010

I’m currently visiting the Boston area because I’m attending EMC World. One of the bigger introductions made here yesterday was actually a new appliance called the VPLEX. In short, the VPLEX is all about virtualizing the access to your block based storage.

Let me give you a quick overview of what I mean with virtualized access to block based storage. With VPLEX, you can take (almost) any block based storage device on a local and remote site, and allow active read and writes on both sides. It’s an active/active setup that allows you to access any storage device via any port when you need to.

You can get two versions right now, the VPLEX local and the VPLEX Metro. Two other version, the VPLEX Geo and the VPLEX Global are planned for early next year. And since there is so much information that can be found online about the VPLEX, I figured I’d create a post here that will help me find the links when I return, and to also give you a one spot that can help you find the info you need.

An overview with links to more information on the EMC VPLEX:

Official links / EMC company bloggers / VMware company bloggers

Blogs and media coverage:

Now, if I missed one or more links, please just send me a tweet or leave a comment and I will make sure that the link is added to this post.


Comments : 7 Comments »
Tags: , , ,
Categories : EMC, Virtualization, VMware, VPLEX

Shorts: How to check the FLARE version of your CLARiiON?

1 04 2010

I decided to introduce something new on my blog. It’s something I’ve decided to call “shorts”. In these shorts I will try to pick some fairly simple and common questions that come up from the searches to my blog and try to give a short descriptive answer to help you out.

So, in this short:

How to check the FLARE version of your CLARiiON?

There are two simple ways to check the release of your FLARE operating environment.

  1. Use the NaviSphere GUI and right click on the array icon inside NaviSphere. Select Properties from the menu and go to the “software” tab. This will give you an overview of all licensed software that is enabled on your array. Should you be in engineering mode, you will find all the software that was pre-loaded on the array, but only those items that have a dash/minus sign in front of them are enabled. In that list of items you should find something like this: 
    FLARE-Operating-Environment 03.26.010.5.016
  2. You can also use the navicli or naviseccli to enter the command “navicli ndu -list -isactive” and get a list of all active software on your array. The entry for your FLARE version would look similar to this: 
    Name of the software package:        FLARE-Operating-Environment
Revision of the software package:    03.26.010.5.016
Commit Required:                     NO
Revert Possible:                     NO
Active State:                        YES
Required packages:                   FA_MIB 260, AnalyzerProvider 260, RPSplitterEngine 260, MVAEngine 260, OpenSANCopy 260, MirrorView 260, SnapView 260, EMCRemoteNG 260, SANCopyProvider 260, SnapViewProvider 260, SnapCloneProvider 260, MirrorProvider 260, CLIProvider 260, APMProvider 260, APMUI 260, AnalyzerUI 260, MirrorViewUI 260, SANCopyUI 260, SnapViewUI 260, ManagementUI 260, ManagementServer 260, Navisphere 260, Base 263
Is installation completed:           YES
Is this System Software:             NO

As you can see, finding out which version of FLARE you have is actually quite simple. Good luck, and let me know if this works for you.


Comments : Leave a Comment »
Tags: , ,
Categories : Clariion, FLARE

The Asymmetrical Logical Unit Access (ALUA) mode on CLARiiON

3 02 2010

I’ve noticed that I have been getting a lot of search engine hits relating to the various features, specifications and problems on the EMC CLARiiON array. One of the searches was related to a feature that has been around for a bit. It was actually introduced in 2001, but in order to give a full explanation I’m just going to start at the beginning.

DetourThe beginning is actually somewhere in 1979 when the founder of Seagate Technology, Alan Shugart, created the Shugart Associates Systems Interface (SASI). This was the early predecessor of SCSI and had a very rudimentary set of capabilities. Only few commands were supported and speeds were limited to 1.5 Mb/s. In 1981, Shugart Associates was able to convince the NCR corporation to team up and thereby convincing ANSI to set up a technical committee to standardize the interface. This was realized in1982 and known as the “X3T9.2 technical committee” and resulted in the name being changed to SCSI.

The committee published their first interface standard in 1986, but would grow on to become the group known now as “International Committee for Information Technology Standards” or INCITS and that is actually responsible for many of the standards used by storage devices such as T10 (SCSI), T11 (Fibre Channel) and T13 (ATA).

Now, in July 2001 the second revision of the SCSI Primary Commands (SPC-2) was published, and this included a feature called Asymmetrical Logical Unit Access mode or in short ALUA mode, and some changes were made in the newer revisions of the primary command set.

Are you with me so far? Good.

On Logical Unit Numbers

Since you came here to read this article I will just assume that I don’t have to explain the concept of a LUN. But what I might need to explain is that it’s common to have multiple connections to a LUN in environments that are concerned with the availability of their disks. Depending on the fabric and the amount of fibre channel cards you have connected you can have multiple paths to the same lun. And if you have multiple paths you might as well use them, right? It’s no good having the additional bandwidth lying around and then not using it.

Since you have multiple paths to the same disk, you need a tool that will somehow merge these paths and tell your operating system that this is the same disk. This tool might even help you achieve a higher throughput since it can balance the reads and writes over all of the paths.

As you might already have guessed there are multiple implementations of this, usually called Multipathing I/O, MPIO or just plainly Multipath, and you will be able to find a solution natively or as an additional piece of software for most modern operating systems.

What might be less obvious is that the connection to these LUNs don’t have to behave in the same way. Depending on what you are connecting to, you have several states for that connection. Or to draw the analogy to the CX4, some paths are active and some paths are passive.

Normally a path to a CLARiiON is considered active when we are connected to the service processor that is currently serving you the LUN. CLARiiON arrays are so called “active/passive” arrays, meaning that only one service processor is in charge of a LUN, and the secondary service processor is just waiting for a signal to take over the ownership in case of a failure. The array will normally receive a signal that tells it to switch from one service processor to the other one. This routine is called a “trespass” and happens so fast that you usually don’t really notice such a failover.

When we go back to the host, the connection state will be shown as active for that connection that is routed to the active service processor, and something like “standby” or “passive” for the connection that goes to the service processor that is not serving you that LUN. Also, since you have multiple connections, it’s not unlikely that the different paths can also have other properties that are different. Things like bandwith (you may have added a faster HBA later) or latency can be different. Due to the characteristics, the target ports might need to indicate how efficient a path is. And if a failure should occur, the link status might change, causing a path to go offline.

You can check the the status of a path to a LUN by asking the port on the storage array, the so called “target port”. For example, you can check the access characteristics of a path by sending the following SCSI command:

  • REPORT TARGET PORT GROUPS (RTPG)

Similar commands exist to actually set the state of a target port.

So where does ALUA come in?

What the ALUA interface does is allow an initiator (your server or the HBA in your server) to discover target port groups. Simply put, a group of ports that provide a common failover behavior for your LUN(s). By using the SCSI INQUIRY response, we find out to what standard the LUN adheres, if the LUN provides symmetric or asymmetric access, and if the LUN uses explicit or implicit failover.

To put it more simply, ALUA allows me to reach my LUN via the active and the inactive service processor. Oversimplified this just means that all traffic that is directed to the non-active service processor will be routed internally to the active service processor.

On a CLARiiON that is using ALUA mode this will result in the host seeing paths that are in an optimal state, and paths that are in an non-optimal state. The optimal path is the path to the active storage processor and is ready to perform I/O and will give you the best performance, and the non-optimal path is also ready to perform I/O but won’t give you the best performance since you are taking a detour.

The ALUA mode is available on CX-3 and CX-4, but the results you get can vary between both arrays. For example if you want to use ALUA with your vSphere installation you will need to use the CX-4 with FLARE 26 or newer and change the failover mode to “4″. Once you have changed the failover mode you will see a slightly different trespass behavior since you can now either manually initiate a trespass (explicit) or the array itself can perform a trespass once it’s noticed that the non-optimal path has received 128,000 or more I/Os than the optimal path (implicit).

Depending on which software you use – PowerPath or for example the native solution – you will find that ALUA is supported or not. You can take a look at Primus ID: emc187614 in Powerlink to get more details on supported configurations. Please note that you need a valid Powerlink account to access that Primus entry.


Comments : 5 Comments »
Tags: , , , , ,
Categories : Clariion, CX3, EMC, GestaltIT, Storage

« Previous Entries


Follow

Get every new post delivered to your Inbox.

Join 1,597 other followers