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VMWare volume, 16% space savings, should it be higher?

I have a 2TB volume on a FAS3020 running OnTap 7.3.2. This volume is shared via NFS and is added as storage for my ESXi 4.1 hosts. I have 29VMs stored on this NFS share, a mixture of Win2003 and Win2008 servers. I have had dedup enabled on this volume for several months. At the command line of the filer I ran:

df -s /vol/VMWare

It says there is a 16% space savings. This seems low. I thought I had read other accounts, as well as Netapp marketing material, that claims space savings for VMWare in the 40-50% range. Any ideas?

I do take snapshots on this volume using SMVI but as I mentioned I have had dedup turned on for months and only keep a few weeks worth of snapshots.

Re: VMWare volume, 16% space savings, should it be higher?

Hi,

How about misalignment? Did you check / fix it on 2003 VMs? (apparently 2008 takes care about alignment on its own)

It proved to be a culprit in some known cases, dramatically reducing de-dupe ratio.

Regards,
Radek

Re: VMWare volume, 16% space savings, should it be higher?

Many months ago I went through and aligned all of my 2003 VMs. In the meantime I have been making a steady transition to Server 2008. Out of my 29 VMs, 11 of them are 2008 now. Should I recheck alignment on my 2003 VMs?

I aligned them when I was running ESX 4.0 and could run mbrscan and mbralign from the ESX console. I am now running ESXi 4.1 which has a very limited console. How do I check alignment under ESXi? I am running VSC 2.0.1, can that check alignment?

Re: VMWare volume, 16% space savings, should it be higher?

How do I check alignment under ESXi? I am running VSC 2.0.1, can that check alignment?

That's a good question on its own!

Have you seen this:

http://communities.netapp.com/click.jspa?searchID=371273&objectType=2&objectID=43696

Re: VMWare volume, 16% space savings, should it be higher?

Can you share the output of "sis status -l" and "snap list" for your NFS volume?

Just curious if dedupe is actually scheduled to run on a regular basis.  Also curious if there are any stale snapshots on the volume.

Re: VMWare volume, 16% space savings, should it be higher?

Here is the output of sis status -l

Path:                    /vol/VMWare
State:                   Enabled
Status:                  Idle
Progress:                Idle for 15:46:36
Type:                    Regular
Schedule:                sun-sat@23
Minimum Blocks Shared:   1
Blocks Skipped Sharing:  0
Last Operation Begin:    Fri Dec  3 23:00:00 EST 2010
Last Operation End:      Fri Dec  3 23:43:14 EST 2010
Last Operation Size:     77 GB
Last Operation Error:    -
Changelog Usage:         0%
Checkpoint Time:         No Checkpoint
Checkpoint Op Type:      -
Checkpoint stage:        -
Checkpoint Sub-stage:    -
Checkpoint Progress:     -

Here is the output of snap list for the VMWare volume

Volume VMWare
working......

  %/used       %/total  date          name
----------  ----------  ------------  --------
  0% ( 0%)    0% ( 0%)  Dec 04 00:06  DRFiler1(0101198753)_VMWare.667 (snapmirror)
  0% ( 0%)    0% ( 0%)  Dec 04 00:04  smvi__ToDR_Snap_recent
  0% ( 0%)    0% ( 0%)  Dec 03 23:30  smvi_ToDR_NoSnap_novmsnap_recent
  0% ( 0%)    0% ( 0%)  Dec 03 00:03  smvi__ToDR_Snap_20101203000002
  0% ( 0%)    0% ( 0%)  Dec 02 23:30  smvi_ToDR_NoSnap_novmsnap_20101202233004
  0% ( 0%)    0% ( 0%)  Dec 02 00:03  smvi__ToDR_Snap_20101202000001
  0% ( 0%)    0% ( 0%)  Dec 01 23:30  smvi_ToDR_NoSnap_novmsnap_20101201233002
  0% ( 0%)    0% ( 0%)  Dec 01 00:03  smvi__ToDR_Snap_20101201000002
  0% ( 0%)    0% ( 0%)  Nov 30 23:30  smvi_ToDR_NoSnap_novmsnap_20101130233002
  0% ( 0%)    0% ( 0%)  Nov 30 00:03  smvi__ToDR_Snap_20101130000002
  0% ( 0%)    0% ( 0%)  Nov 29 23:30  smvi_ToDR_NoSnap_novmsnap_20101129233002
  0% ( 0%)    0% ( 0%)  Nov 29 00:30  smvi__Test_20101129003001
  0% ( 0%)    0% ( 0%)  Nov 29 00:04  smvi__ToDR_Snap_20101129000002
  0% ( 0%)    0% ( 0%)  Nov 28 23:30  smvi_ToDR_NoSnap_novmsnap_20101128233002
  0% ( 0%)    0% ( 0%)  Nov 28 17:07  smvi__Test_20101128170641
  0% ( 0%)    0% ( 0%)  Nov 28 16:58  smvi__Test_20101128165725
  0% ( 0%)    0% ( 0%)  Nov 28 16:52  smvi__Test_20101128165141
  0% ( 0%)    0% ( 0%)  Nov 28 13:58  smvi__Test_20101128135737
  0% ( 0%)    0% ( 0%)  Nov 28 13:47  smvi__Test_20101128134629
  0% ( 0%)    0% ( 0%)  Nov 28 13:13  smvi__Test_20101128131235
  0% ( 0%)    0% ( 0%)  Nov 28 09:59  smvi__Test_20101128095849
  0% ( 0%)    0% ( 0%)  Nov 28 09:51  smvi__Test_20101128095058
  0% ( 0%)    0% ( 0%)  Nov 28 00:04  smvi__ToDR_Snap_20101128000003
  0% ( 0%)    0% ( 0%)  Nov 27 23:30  smvi_ToDR_NoSnap_novmsnap_20101127233002
  0% ( 0%)    0% ( 0%)  Nov 27 00:03  smvi__ToDR_Snap_20101127000002
  0% ( 0%)    0% ( 0%)  Nov 26 23:30  smvi_ToDR_NoSnap_novmsnap_20101126233002
  0% ( 0%)    0% ( 0%)  Nov 26 00:03  smvi__ToDR_Snap_20101126000003
  0% ( 0%)    0% ( 0%)  Nov 25 23:30  smvi_ToDR_NoSnap_novmsnap_20101125233002
  0% ( 0%)    0% ( 0%)  Nov 25 00:03  smvi__ToDR_Snap_20101125000003
  0% ( 0%)    0% ( 0%)  Nov 24 23:30  smvi_ToDR_NoSnap_novmsnap_20101124233002
  0% ( 0%)    0% ( 0%)  Nov 24 00:03  smvi__ToDR_Snap_20101124000002
  0% ( 0%)    0% ( 0%)  Nov 23 23:30  smvi_ToDR_NoSnap_novmsnap_20101123233004
  0% ( 0%)    0% ( 0%)  Nov 23 00:03  smvi__ToDR_Snap_20101123000003
  0% ( 0%)    0% ( 0%)  Nov 22 23:30  smvi_ToDR_NoSnap_novmsnap_20101122233003
  0% ( 0%)    0% ( 0%)  Nov 22 00:03  smvi__ToDR_Snap_20101122000003
  0% ( 0%)    0% ( 0%)  Nov 21 23:30  smvi_ToDR_NoSnap_novmsnap_20101121233002
  0% ( 0%)    0% ( 0%)  Nov 21 00:03  smvi__ToDR_Snap_20101121000003
  0% ( 0%)    0% ( 0%)  Nov 20 23:30  smvi_ToDR_NoSnap_novmsnap_20101120233002
  0% ( 0%)    0% ( 0%)  Nov 20 00:04  smvi__ToDR_Snap_20101120000002
  0% ( 0%)    0% ( 0%)  Nov 19 23:30  smvi_ToDR_NoSnap_novmsnap_20101119233002
  0% ( 0%)    0% ( 0%)  Nov 19 00:07  smvi__ToDR_Snap_20101119000003
  0% ( 0%)    0% ( 0%)  Nov 18 23:30  smvi_ToDR_NoSnap_novmsnap_20101118233002
  0% ( 0%)    0% ( 0%)  Nov 18 00:06  smvi__ToDR_Snap_20101118000002
  0% ( 0%)    0% ( 0%)  Nov 17 23:30  smvi_ToDR_NoSnap_novmsnap_20101117233001
  0% ( 0%)    0% ( 0%)  Nov 17 00:09  smvi__ToDR_Snap_20101117000002
  0% ( 0%)    0% ( 0%)  Nov 16 23:30  smvi_ToDR_NoSnap_novmsnap_20101116233002
  0% ( 0%)    0% ( 0%)  Nov 16 00:03  smvi__ToDR_Snap_20101116000003
  0% ( 0%)    0% ( 0%)  Nov 15 23:30  smvi_ToDR_NoSnap_novmsnap_20101115233003
  0% ( 0%)    0% ( 0%)  Nov 15 00:03  smvi__ToDR_Snap_20101115000003
  0% ( 0%)    0% ( 0%)  Nov 14 23:30  smvi_ToDR_NoSnap_novmsnap_20101114233001
  0% ( 0%)    0% ( 0%)  Nov 14 00:03  smvi__ToDR_Snap_20101114000002
  0% ( 0%)    0% ( 0%)  Nov 13 23:30  smvi_ToDR_NoSnap_novmsnap_20101113233001
  0% ( 0%)    0% ( 0%)  Nov 13 00:03  smvi__ToDR_Snap_20101113000002
  0% ( 0%)    0% ( 0%)  Nov 12 23:30  smvi_ToDR_NoSnap_novmsnap_20101112233002
  0% ( 0%)    0% ( 0%)  Nov 12 00:02  smvi__ToDR_Snap_20101112000002
  0% ( 0%)    0% ( 0%)  Nov 11 23:30  smvi_ToDR_NoSnap_novmsnap_20101111233002
  0% ( 0%)    0% ( 0%)  Nov 11 00:03  smvi__ToDR_Snap_20101111000003
  0% ( 0%)    0% ( 0%)  Nov 10 23:30  smvi_ToDR_NoSnap_novmsnap_20101110233002
  0% ( 0%)    0% ( 0%)  Nov 10 00:02  smvi__ToDR_Snap_20101110000002
  0% ( 0%)    0% ( 0%)  Nov 09 23:30  smvi_ToDR_NoSnap_novmsnap_20101109233002
  0% ( 0%)    0% ( 0%)  Nov 09 00:03  smvi__ToDR_Snap_20101109000001
  0% ( 0%)    0% ( 0%)  Nov 08 23:30  smvi_ToDR_NoSnap_novmsnap_20101108233001
  0% ( 0%)    0% ( 0%)  Nov 08 00:02  smvi__ToDR_Snap_20101108000002
  0% ( 0%)    0% ( 0%)  Nov 07 23:30  smvi_ToDR_NoSnap_novmsnap_20101107233001
  0% ( 0%)    0% ( 0%)  Nov 07 00:04  smvi__ToDR_Snap_20101107000002
  0% ( 0%)    0% ( 0%)  Nov 06 23:30  smvi_ToDR_NoSnap_novmsnap_20101106233001
  0% ( 0%)    0% ( 0%)  Nov 06 00:02  smvi__ToDR_Snap_20101106000002
  0% ( 0%)    0% ( 0%)  Nov 05 23:30  smvi_ToDR_NoSnap_novmsnap_20101105233001
  0% ( 0%)    0% ( 0%)  Nov 05 00:03  smvi__ToDR_Snap_20101105000002
  0% ( 0%)    0% ( 0%)  Nov 04 23:30  smvi_ToDR_NoSnap_novmsnap_20101104233003
  0% ( 0%)    0% ( 0%)  Nov 04 00:03  smvi__ToDR_Snap_20101104000003
  0% ( 0%)    0% ( 0%)  Nov 03 23:30  smvi_ToDR_NoSnap_novmsnap_20101103233003
  0% ( 0%)    0% ( 0%)  Nov 03 00:03  smvi__ToDR_Snap_20101103000001
  0% ( 0%)    0% ( 0%)  Nov 02 23:30  smvi_ToDR_NoSnap_novmsnap_20101102233001
  0% ( 0%)    0% ( 0%)  Nov 02 00:02  smvi__ToDR_Snap_20101102000001
  0% ( 0%)    0% ( 0%)  Nov 01 23:30  smvi_ToDR_NoSnap_novmsnap_20101101233001
  0% ( 0%)    0% ( 0%)  Nov 01 00:02  smvi__ToDR_Snap_20101101000001
  0% ( 0%)    0% ( 0%)  Oct 31 23:30  smvi_ToDR_NoSnap_novmsnap_20101031233001
  0% ( 0%)    0% ( 0%)  Oct 31 08:30  smvi__ToDR_Snap_20101031082823
  0% ( 0%)    0% ( 0%)  Oct 31 07:33  smvi_ToDR_NoSnap_novmsnap_20101031073328

Here is the output of df -s for the volume VMWare

Filesystem                used      saved       %saved
/vol/VMWare/        1038750724  200134740          16%

I have Netapp's VSC 2.0.1 installed on our VirtualCenter server. It reports that the last time that dedup was run was October 28th. The sis status command shows that the last time it was run was last night. I have it scheduled to run each evening.

Re: VMWare volume, 16% space savings, should it be higher?

Hendersond,

To check the read/write alignment at the storage system, you can directly view the counters lun:unaligned_reads, lun:unaligned_writes (stats show).

You can even install DFM (4.0) and use Performance Advisor (Performance diagnosis feature) to check for lun mis-alignments.

Regards,

Bhanu

Re: VMWare volume, 16% space savings, should it be higher?

In my case, I am using an NFS share (file level storage) not a LUN (block level storage) for my VM storage. My understanding is misalignment in my case can only happen at the guest operating system level and only with Windows Server 2003. Windows Server 2008 is always aligned. How can I check OS alignment for my Win2003 servers when I am running ESXi 4.1? I do not think any of them are misaligned but it is worth checking.

Re: VMWare volume, 16% space savings, should it be higher?

Are any of theses snapshots from before dedupe was enabled?

-----

FWIW, we have almost 3 TB of misaligned VMs deduping just fine up to 80%+ space savings...

Re: VMWare volume, 16% space savings, should it be higher?

I have had dedup enabled for over 6 months so no, none of the snapshots are before dedup was turned on. This is puzzling, I was hoping for something in the 40-50% range. Is there a possibility that the df -s output is just incorrect and I really have great dedup?