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 Post subject: Volume Conversion Questions
PostPosted: Sun May 26, 2019 1:04 am 

Joined: Sun May 26, 2019 12:51 am
Posts: 8
Hi, new here, first post.

I have some questions about virtual volume conversion. We have an all flash 8200 and a recent firmware upgrade 3.3.1 mu2 made compression available.

If I convert a Solaris virtual volume from an old v2 dedup volume to a new v3 compressed volume in a new CPG will the Solaris system be affected at all, LUN ID changes or WWN changes?

The volume is 8 TB, but only 2.2TB used due to deduplication, how much free space am I likely to need to complete the conversion? No raid level changes.

Also, any idea how long 8TB will take to convert? whole system does less than 7000 IOPS most of the time, assuming the conversion will be a background process?

Thanks in advance.


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 Post subject: Re: Volume Conversion Questions
PostPosted: Sun May 26, 2019 6:17 pm 

Joined: Tue Mar 29, 2016 9:32 pm
Posts: 99
Hello!

If you convert the volume the WWN, name and exported vLUN will stay the same, the Udid will most likely change though, but Solaris probably won't care/notice.

An 8200 is classed as a bit too weedy for compression but should be OK for light data loads (see what your CPU load is before and after, it would be interesting).
- HPE engineering only gave us the green light to install 3.3.1 on our 8400/8200 systems if we promised not to use compression.

You can do a compression estimate with the "checkvv -dedup_compr_dryrun <volumename>" command, might give you an idea of how long the actual compress would take.

Keep us all posted on how it goes, stats are always interesting :-)

Mark


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 Post subject: Re: Volume Conversion Questions
PostPosted: Sun May 26, 2019 7:17 pm 

Joined: Sun May 26, 2019 12:51 am
Posts: 8
Thanks Mark,

Is there a way to change the UDID, I am asking some Solaris guys about it, but my guess is they will freak out and tell us to not to change anything at all.

Dry run started, will see what comes back.


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 Post subject: Re: Volume Conversion Questions
PostPosted: Sun May 26, 2019 7:28 pm 

Joined: Tue Mar 29, 2016 9:32 pm
Posts: 99
"setvv" can change udid of a volume.

I'm 99.9% sure that Solaris doesn't use the UDID, it cares about the WWN and LUN, that's all I ever give the UNIX guys here, and they have volume snapshots being refreshed all over the place with no ill effects.


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 Post subject: Re: Volume Conversion Questions
PostPosted: Sun May 26, 2019 8:48 pm 

Joined: Sun May 26, 2019 12:51 am
Posts: 8
Dry run for compression states 7.8TB down to 3.3TB, Ratio of 2.36. Which is probably about what I was expecting. Out of interest that is on par with our old IBM V7000 with compression.

Looking at other options

If I clone the V2 deduped virtual volume to another CPG with v3 compression available would I then be able to enable compression by ticking the box on the cloned vv? Is that even an option.

Any other options? I do not have a huge amount of space to play with so if the 3PAR can do this conversion that would be the better option I think.

Mark I will pass on your statements.

Thanks


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 Post subject: Re: Volume Conversion Questions
PostPosted: Sun May 26, 2019 9:00 pm 

Joined: Sun May 26, 2019 12:51 am
Posts: 8
Is there a way to get the current UDID for the VV?


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 Post subject: Re: Volume Conversion Questions
PostPosted: Sun May 26, 2019 11:26 pm 

Joined: Tue Mar 29, 2016 9:32 pm
Posts: 99
Hiya,

If you have the space available to be able to create the volume in the "v3" CPG then you can just use the "tunevv" command, it'll do the copy and switch over on the fly, hosts don't see the change. Just needs enough space to do the move, it'll delete the old volume once complete and you'll get that space back eventually, or you can hurry it along with a compactcpg.
- also you can keep the old volume as well if you use the option "-keepvv <VV_name>" and have space.

To see the udid .. run "showvv -d" .. last column shows it.


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 Post subject: Re: Volume Conversion Questions
PostPosted: Sun May 26, 2019 11:45 pm 

Joined: Sun May 26, 2019 12:51 am
Posts: 8
Thanks Mark.

I almost have enough space. It is 7.9TB, using only 3.3 TB with V2 compaction.

I have 7.2TB free at the moment, I might be able to find a couple of TB, but if it is using only 3.3 TB would I need 7.9TB+ free?

Once it is moved I can delete the old CPG and free up 14TB Used and 21TB of reserved space.


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 Post subject: Re: Volume Conversion Questions
PostPosted: Tue May 28, 2019 2:54 am 

Joined: Sun May 26, 2019 12:51 am
Posts: 8
If I select a tune to another CPG it states "A convert action will be performed to tune and move the virtual volumes to the specified CPG"

So I guess this means the UDID could change and possibly cause problems. Or does a tune that converts not change the UDID?


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 Post subject: Re: Volume Conversion Questions
PostPosted: Tue May 28, 2019 3:00 am 

Joined: Tue Mar 29, 2016 9:32 pm
Posts: 99
I'd say the udid would change, but solaris won't care.

Youcould test it .. create a 1GiB volume in the old CPG, note down it;s udid and then convert it to the new CPG and see what happens. Could even prove it further by having it exported to a test Solaris server.


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