Gentoo Archives: gentoo-user

From: Pandu Poluan <pandu@××××××.info>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Safeguarding strategies against SSD data loss
Date: Tue, 28 Oct 2014 00:41:57
In Reply to: Re: [gentoo-user] Safeguarding strategies against SSD data loss by Rich Freeman
1 On Oct 28, 2014 12:31 AM, "Rich Freeman" <rich0@g.o> wrote:
2 >
3 > On Mon, Oct 27, 2014 at 12:52 PM, Pandu Poluan <pandu@××××××.info> wrote:
4 > >
5 > > ZoL (ZFS on Linux) nowadays is implemented using DKMS instead of FUSE,
6 thus
7 > > running in kernelspace, and (relatively) easier to put into an
8 initramfs.
9 >
10 > Sorry about that. I should have known that, but for some reason I got
11 > that memory crossed in my brain... :)
12 >
13 > > vdevs can grow, but they can't (yet) shrink.
14 >
15 > Can you point to any docs on that, including any limitations/etc? The
16 > inability to expand raid-z the way you can do so with mdadm was one of
17 > the big things that has been keeping me away from zfs. I understand
18 > that it isn't so important when you're dealing with large numbers of
19 > disks (backblaze's storage pods come to mind), but when you have only
20 > a few disks being able to manipulate them one at a time is very
21 > useful. Growing is the more likely use case than shrinking. Then
22 > again, at some point if you want to replace smaller drives with larger
23 > ones you might want a way to remove drives from a vdev.
24 >
26 First, you need to set your pool to "autoexpand=on".
28 Then, one by one, you offline a disk within the vdev and replace it with a
29 larger one. After all disks have been replaced, do a scrub, and ZFS will
30 automagically enlarge the vdev.
32 If you're not using whole disks as ZFS, then s/replace with larger/enlarge
33 the partition/.
35 Rgds,
36 --


Subject Author
Re: [gentoo-user] Safeguarding strategies against SSD data loss Rich Freeman <rich0@g.o>