[zfs-discuss] FW: Setting default user/group quotas?
-Original Message- From: Fred Liu Sent: 星期二, 四月 24, 2012 11:41 To: develo...@lists.illumos.org Subject: Setting default user/group quotas? It seems this feature is still not there yet. Any plan to do it? Or is it hard to do it? Thanks. Fred ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Two disks giving errors in a raidz pool, advice needed
On Tue, Apr 24, 2012 at 12:16 AM, Matt Breitbach matth...@flash.shanje.comwrote: So this is a point of debate that probably deserves being brought to the floor (probably for the umpteenth time, but indulge me). I've heard from several people that I'd consider experts that once per year scrubbing is sufficient, once per quarter is _possibly_ excessive, and once a week is downright overkill. Since scrub thrashes your disk, I'd like to avoid it if at all possible. My opinion is that it depends on the data. If it's all data at rest, ZFS can't correct bit-rot if it's not read out on a regular interval. My biggest question on this? How often does bit-rot occur on media that isn't read or written to excessively, but just spinning most of the day and only has 10-20GB physically read from the spindles daily? We all know as data ages, it gets accessed less and less frequently. At what point should you be scrubbing that old data every few weeks to make sure a bit or two hasn't flipped? FYI - I personally scrub once per month. Probably overkill for my data, but I'm paranoid like that. -Matt -Original Message- How often do you normally run a scrub, before this happened? It's possible they were accumulating for a while but went undetected for lack of read attempts to the disk. Scrub more often! -- Dan. Personally unless the dataset is huge and you're using z3, I'd be scrubbing once a week. Even if it's z3, just do a window on Sunday's or something so that you at least make it through the whole dataset at least once a month. There's no reason NOT to scrub that I can think of other than the overhead - which shouldn't matter if you're doing it during off hours. --Tim ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Two disks giving errors in a raidz pool, advice needed
On 2012-04-24 19:14, Tim Cook wrote: Personally unless the dataset is huge and you're using z3, I'd be scrubbing once a week. Even if it's z3, just do a window on Sunday's or something so that you at least make it through the whole dataset at least once a month. +1 I guess Among other considerations, if the scrub does find irrepairable errors, you might have some recent-enough backups or other sources of the data, so the situation won't be as fatal as when you look for errors once a year ;) There's no reason NOT to scrub that I can think of other than the overhead - which shouldn't matter if you're doing it during off hours. I heard a rumor that HDDs can detect reading flaky sectors (i.e. detect a bit-rot error and recover thanks to ECC), and in this case they would automatically remap the revocered sector. So reading the disks in (logical) locations where your data is known to be may be a good thing to prolong its available life. This of course relies kinda on disk reliability - i.e. it should be rated 24/7 and within warranted age (mechanics should be within acceptable wear). No guarantees with other drives, although I don't think weekly scrubs would be fatal. If only ZFS could queue scrubbing reads more linearly... ;) //Jim ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Two disks giving errors in a raidz pool, advice needed
On Apr 24, 2012, at 8:35 AM, Jim Klimov wrote: On 2012-04-24 19:14, Tim Cook wrote: Personally unless the dataset is huge and you're using z3, I'd be scrubbing once a week. Even if it's z3, just do a window on Sunday's or something so that you at least make it through the whole dataset at least once a month. It depends. There are cascading failure modes in your system that are not media related and cause bring your system to its knees. Scrubs and resilvers can trigger or exacerbate these. +1 I guess Among other considerations, if the scrub does find irrepairable errors, you might have some recent-enough backups or other sources of the data, so the situation won't be as fatal as when you look for errors once a year ;) There is considerable evidence that scrubs propagate errors for some systems (no such evidence for ZFS systems). So it is not a good idea to have a blanket scrub policy with high frequency. There's no reason NOT to scrub that I can think of other than the overhead - which shouldn't matter if you're doing it during off hours. I heard a rumor that HDDs can detect reading flaky sectors (i.e. detect a bit-rot error and recover thanks to ECC), and in this case they would automatically remap the revocered sector. So reading the disks in (logical) locations where your data is known to be may be a good thing to prolong its available life. It is a SMART feature and the disks do it automatically for you. -- richard -- ZFS Performance and Training richard.ell...@richardelling.com +1-760-896-4422 ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
