This is a fairly recent illumos kernel, and sounds very strange that snapshotting zvol would require usage space: isn't one of the best zfs options zero usage space snapshot at creation time? Also, I have other hardware systems with zvol shared over iscsi/fc to vmware, hosting vmdk of systems running on vmware, and snapshots show very low usage there. zpool list shows NAME SIZE ALLOC FREE EXPANDSZ CAP DEDUP HEALTH ALTROOT data2 1.62T 998G 658G - 60% 1.00x ONLINE - zfs list shows NAME USED AVAIL REFER MOUNTPOINT data2 793G 293G 40.0K /data2 data2/myvolume 792G 421G 664G - Looks like the numbers here are confusing. Where's the clue?? ---------------------------------------------------------------------------------- Da: Jim Klimov A: [email protected] Gabriele Bulfon Data: 22 marzo 2014 15.52.11 CET Oggetto: Re: [discuss] snapshot: out of space 22 ????? 2014 ?. 15:24:14 CET, Gabriele Bulfon ?????: Hi, I have a situation where a customer running illumos under vmware, created a raidz zpool, composed of 3 vmware disks, for a total of 700GB available space. Then it created a single volume of almost 700GB, shared as an iscsi resource, used by another server. When trying to snapshot the zpool, it says "out of space" in the volume fs. No way to create snapshots. I thought that the volume had reserved the space, so I had no space for snapshots. So I added 3 vmdisks of 43GB each, then expanded the pool with a raidz of the new three disks. So now I have the pool with two raidz, for a total of almost 1.1TB. Still, can't snapshot the volume....."out of space". Besides the fact that this vmware situation is very strange and maybe silly, what may be the reason for this? Thanks for any help Gabriele. ------------------------------------------- illumos-discuss Archives: https://www.listbox.com/member/archive/182180/=now RSS Feed: https://www.listbox.com/member/archive/rss/182180/22642773-76f3f1fc Modify Your Subscription: https://www.listbox.com/member/?&; Powered by Listbox: http://www.listbox.com Zvol snapshots by default reserve enough space to guarantee their ability to be fully overwritten. That is, reservation would increase roughly by 'used' upon every snapshot. And i think the first snapshot starts this, doubling the reserved space requirements for the zvol as soon as the snapshot is made. At least that's what i saw on some older versions of zfs. There are some attributes to disable such behaviour, but you may lose guarantees to fill up the live dataset of the zvol, if some other datasets (including its own snapshots) consume the available pool space. -- Typos courtesy of K-9 Mail on my Samsung Android ------------------------------------------- illumos-discuss Archives: https://www.listbox.com/member/archive/182180/=now RSS Feed: https://www.listbox.com/member/archive/rss/182180/21175541-02f10c6f Modify Your Subscription: https://www.listbox.com/member/?&id;secret=21175541-29e3e0ee Powered by Listbox: http://www.listbox.com
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