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EVA 8000 LUN management and replication

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mujzeptu
Super Advisor

EVA 8000 LUN management and replication

I have an EVA 8000.

We are going to have 100 LUNs that will have the exact same data on them. Once a unique individual connects to their own LUN (via iSCSI kit or a linux server connected to the EVA sharing out iSCSI targets).

Anyway, once a unique individual connects to their own LUN, they will modify and use their data alone. The LUN's host vmware linked clones. So, when new OS updates come out, we will want to update one set (LUN) and distribute it out to everyone thus overwriting their data/LUN.

So - my questions are:

- What is the easiest way of replicating a LUN? Can I just create a master LUN and easily through command view copy it over to all other LUNs? Does this cause connectivity issues for the unique clients?

- Also, im guessing snapshots/snapclones/mirrorclones come into play. Can I get additional benefits from these tools? Can I use this for backups, restores, etc?
11 REPLIES
mujzeptu
Super Advisor

Re: EVA 8000 LUN management and replication

Additionally, how much throughput and clients can the iscsi kit take? If its only 2 ports, cant that be saturated pretty easily?
IBaltay
Honored Contributor
Solution

Re: EVA 8000 LUN management and replication

Hi,
have a look in this document pls, the snapclone feature could be use for your task:
http://www.aktuality.sk/spravy/komentare/komentar-holy-strach?&i9=0a6fc8109173
page 50-51,
replication template (via the snapclone) of the single volume multiple times

commands
snapclonehostvolume - page 159
snapclonestoragevolume - page 166


the snapclone guidelines:
http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c01376136/c01376136.pdf
page 14,
add snapclone -> page 27

note

these documents covers also snapshots/snapclones/mirrorclones ... and their usage



the pain is one part of the reality
IBaltay
Honored Contributor

Re: EVA 8000 LUN management and replication

the EVA iSCSI stuff with all the guidelines is described here:
http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c01519273/c01519273.pdf
the pain is one part of the reality
IBaltay
Honored Contributor

Re: EVA 8000 LUN management and replication

Sorry for the bad link in my first post, seemingly the current financial crisis interests me as well as snapshots :-))...
the correct link is the following:
http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c01519273/c01519273.pdf
the pain is one part of the reality
IBaltay
Honored Contributor

Re: EVA 8000 LUN management and replication

no, it is this :-((:
http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c01489905/c01489905.pdf
the pain is one part of the reality
McCready
Valued Contributor

Re: EVA 8000 LUN management and replication

To do this task, you should use either RSM or SSSU scripting which would allow you to automate the operation of using a master lun as the source (you might want several master luns for this). SSSU might be more comfortable for those who like command line interfaces, and RSM for those with a graphical preference. Note that RSM cannot do all that SSSU can, but for your needs, either should suffice. Most likely you will need to unpresent the lun from the host prior to replacing it.


For your needs, the biggest performance issue will be how quickly do you need to make the 100 copies (probably via Snapclones). In order to get some idea of the load, you can use the EVAPerf tool, most easily through the Perfmon interface on the Windows Server management station to get a feel for what the workload is once you start a certain number of copies, or via the command-line interface where you can slice/dice the comma seperated data in Excel or a tool like TLVIZ. It is probably good to create a benchmark of your performance earlier rather than later.

check out evamgt.wetpaint.com and evamgt google group
mujzeptu
Super Advisor

Re: EVA 8000 LUN management and replication

Ok great.

Well, while the data is identical, its only identical at the beginning, then each user modifies the set data and makes it their own.

I'd say probably once every couple of months I could have a maintenance window to update the master set, then copy it out to the other LUN's.

So, I would use snapclones via RSM (what is RSM) to make copies of the LUN? Is it the mirrorclones that auto replicate? Because we want to make sure each LUN is unique UNTIL our maintenance window to copy out the master.
Uwe Zessin
Honored Contributor

Re: EVA 8000 LUN management and replication

RSM means "Replication Solutions Manager" - it is a framework to automate BC (Business Copy = 'local replication' within a single storage array) and CA (Continuous Access = 'remote replication' between two EVAs) tasks. It has script templates for a number of common tasks which can serve as examples how to do things.


You can pretend that a 'mirror clone' is a set of two virtual disks which are kept identical until you 'separate' them - either temporary (the EVA keeps a difference bitmap to allow a resync) or permamently (the result is two independend virtual disks).

But you can only clone one virtual disk to another one, not to multiple ones concurrently.


How large is the time window during which you can create 100 new up-to-date copies? I'm skeptical that it works in a reasonable amount of time.
- snapclone from one master copy = 2 copies
- snapclone from them = 4 copies
- snapclone from them = 8 copies
...
I expect that this will cause too much I/O activity when 4 or even 8 copies are competing for I/O within a single disk group.
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mujzeptu
Super Advisor

Re: EVA 8000 LUN management and replication

Thanks for the responses.

Well, its only going to be like once every 2-4 months, depending on updates, etc.

I guess the window is what it needs to be. The only other alternative is to use the network to copy them over or present all 100 LUNs to one machine, that then has a local copy of all the data to copy over....

I mean, whats a ball-park guess? Are we talking 2 hours, 12 hours, 80 hours?
mujzeptu
Super Advisor

Re: EVA 8000 LUN management and replication

Oh, i guess I should say the size of the 100 LUN's will be only 60GB for now, but eventually will be 1.4TB.

Uwe Zessin
Honored Contributor

Re: EVA 8000 LUN management and replication

I have not tried to measure the clone speeds myself, but have a dim memory, that it was once said it was about 100 GigaBytes per hour. Of course, if there is a lot I/O activity (like from other clone operations) I'd expect the speed to be less.
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