On Friday, August 5, 2016, matthew patton <pattonme@xxxxxxxxx> wrote:
> - ESXI's VMFS5 is aligned on 1MB, so 4MB discards never actually free anything
the proper solution here is to:
* quit worrying about it and buy sufficient disk in the first place, it's not exactly expensive
I would do that for one or a couple environments, or if I sold drives :). However, the two use cases that are of importance to my group still warrant figuring this out:
- Large medical image collections or frequently modified database files (quite a few deletes and creates)
- Passing VMWare certification. It means a lot to people without deep dtorage knowledge, to make a decision on adopting a technology
* ask VMware to have the decency to add a flag to vmkfstools to specify the offset
Preaching to the choir! I will ask. Hope someone will listen.
* create a small dummy VMFS on the block device that allows you to create a second filesystem behind it that's aligned on a 4MB boundary. Or perhaps simpler, create a thick-zeroed VMDK (3+minimum size + extra) on the VMFS such that the next VMDK created falls on the desired boundary.
I wonder how to do this for the test, or use a small partition like Vlad described. I will try that with one of their unmap tests
* use NFS like *deity* intended like any other sane person, nobody uses block storage anymore for precisely these kinds of reasons.
Working in that direction too. A bit concerned of the double writes of the backing filesystem, then double writes for RADOS. Per Nick, this still works better than block. But having gone through 95% of certification for block, I feel like I should finish it before jumping on to the next thing.
Thank you for your input, it is very practical and helpful long term.
Alex
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Alex Gorbachev
Storcium
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