VMware vSphere

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  • 1.  Sdelete -z or -c???

    Posted Oct 20, 2011 05:32 AM

    I've been reading some older forums which mention sdelete -c was for zeroing out space, then in a later versions sdelete -z was adding for cleaning (adding random bits), in my version (1.6) -z is zero and -c is clean (makes sense really).

    So can I just clarify that to take advantage of my Thin Provisioning at both ESX and SAN level (3PAR with zero detect), I should run sdelete -c on the guest OS, then dd if=/dev/zero of=xxx.zero... at the ESX level?



  • 2.  RE: Sdelete -z or -c???

    Posted Oct 20, 2011 07:33 AM

    Doing the zeroes at the VM level wont help with VMware's thin provisioning (they dont do zero detect), but it would help recover space on your 3PAR array.

    Do whatever option writes zeroes :smileyhappy:



  • 3.  RE: Sdelete -z or -c???

    Posted Oct 20, 2011 12:46 PM

    AFAIK running "sdelete -z <drive>" from within the VM is exact what is required to shrink a thin provisioned disk, if you have svMotion (you need to move the disk to get it smaller). There are many threads around that here (search for "thin" and "sdelete") and its the way I shrink "my" disks.

    AWo



  • 4.  RE: Sdelete -z or -c???

    Posted Oct 20, 2011 05:14 PM

    Sure, if you do a 2 stage process of writing zeroes in a VM then a vmotion, it will shrink down.  But compare that to the array side where its 0 extra steps.



  • 5.  RE: Sdelete -z or -c???

    Posted Oct 21, 2011 07:49 AM

    My answer was just regarding your statement that VMware won't use zeroed blocks to shrink.

    AWo



  • 6.  RE: Sdelete -z or -c???

    Posted Oct 20, 2011 09:57 PM

    Also, what sort of times are people getting running sdelete? I kicked one off yesterday and it's been 16 hours and still on'y at 60%. So I'm looking at 24hours to run this, is that normal (Volume is 4TB)?



  • 7.  RE: Sdelete -z or -c???

    Posted Oct 24, 2011 06:10 AM

    Thats about 43MB/sec, which isn't unreasonable.