AllBlack
Expert
Expert

LUN Migration - Best practice?

Hi all,

This question might be more suited for the EMC forums but I will give it a go anyway.

Our current ESX storage sits mainly on a Clariion C3-20. One of the problems is that

when we needed space we just took it without paying too much attention to the underlying disk infrastructure.

We have a lot of low-usage/development VMs sitting on fibre channel disk and we would like to move these

LUNs to the SATAII shelves.

What is the best way to go about this with a minimal disruption?

Navisphere manager migrates LUN while keeping its settings intact but I wonder how ESX reacts to it?

Maybe it is better to create new LUN and svmotion the machines?

Any thoughts?

Cheers

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11 Replies
weinstein5
Immortal
Immortal

The best way is to use svmotion - it is what it is designed for to move a VM from one LUN to another with no downtime -

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proden20
Hot Shot
Hot Shot

svmotion your machines

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AllBlack
Expert
Expert

Obviously svmotion would work very well on a per VM basis.

I was wondering if anyone tried using Clariion's virtual LUN technology?

According to the "VMware ESX Server using EMC Clarion storage systems

solutions guide" :

CLARiiON Virtual LUN technology allows users to reconfigure the backend storage

allocated to a LUN. The reconfiguration can be performed while the LUN is online and

without disruption to the host application. Usage examples include migration from one

RAID group to another; optionally changing the data protection scheme; or even

changing the physical drive type. This feature is often used in implementing information

lifecycle management (ILM) as the back-end characteristics can be changed as

performance and availability requirements change. Virtual LUN technology is

implemented by performing a block-by-block migration from a source LUN to a target

LUN. When the migration is complete, the target LUN retains all the attributes of the

source LUN including the world wide name (WWN), LUN ID and logical unit number,

making the migration completely transparent to the attached host. At the successful

completion of the migration, the original source LUN is unbound, freeing up the disk space for other uses.Additionally, a source LUN can be migrated to a larger target to increase the capacity. LUN migration is managed through Navisphere Manager. The Migrate option invokes adialog that allows the user to select the destination and rate of the migration for the session. The migration rate and the number of concurrent migration sessions can be setto minimize performance impact. A set of CLI commands are also available for managing migrations.

The following migration rules apply:

♦ Source and destination LUNs must reside on the same storage system.

♦ Source and destination LUN can be in the same or different RAID groups.

♦ Any public LUN or metaLUN can migrate to any LUN or metaLUN of equal or

larger size.

♦ RAID type of source and target LUN can be different.

♦ The source and target LUNs can be on disks of different type (Fibre Channel or

ATA, 2 Gb/s or 4 Gb/s disk speeds)

Any thoughts? If I can do it on a per LUN basis I would prefer that.

Cheers

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weinstein5
Immortal
Immortal

I have not used but if they it is transparent to the ESX Host - it should work -

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mcowger
Immortal
Immortal

If the vLUN technology maintains the same SCSI VPD values, I would use that.






--Matt

--Matt VCDX #52 blog.cowger.us
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AllBlack
Expert
Expert

I suppose there is only one way to find out and that is to test it Smiley Wink

I will keep you posted.

cheers

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proden20
Hot Shot
Hot Shot

if you have a clariion you have emc support...i'd suggest calling them.

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cdodson2
Enthusiast
Enthusiast

I have migrated all sorts of LUNs on Clariions for several years now (since Flare 19 anyway) without issue. You can migrate your FC-based VMFS to an equal or larger sized LUN on SATA disk using the LUN Migration wizard. Just be sure you are current with your Flare code, your SAN has proper failover, etc. In other words, test first as I can't say with 100% certainty (does such a thing exist in our world?) you won't have an issue.

It's terribly easy and requires no reconfiguration or downtime whatsoever with ESX. In other words "it just works"...

CD

Cooldude09
Commander
Commander

I wouls suggest you for cloning as this will also give you a backup. Once cloned, you can play with the LUN's the way they needs to be created.

Regards

Anil

Save the planet, Go Green

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Nick_F
Enthusiast
Enthusiast

Definitely just do a LUN migration within Navisphere, it works great and is invisible to the host (ESX servers included). The only issue I find with it is it takes ages (last one I did was a 150GB LUN from one set of FC 15k drives to another set and it took 16 hours), that is running mostly on Low priority though. Whilst the migration is running it has very little impact on SAN performance (unless you set the priority to ASAP).

AllBlack
Expert
Expert

Hey guys,

I did a test and it all worked fine. Yes, it is slow (I used fast settings), I estimate it took about 12 hours for a 150GB LUN.

All settings are kept intact and data added during migration is all there.

I am positive that creating a new LUN and use svmotion is quicker but I think I will stick with the navisphere method because of its ease of use.

Cheers

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