Date: Tue, 14 Jul 2015 09:46:15 -0700 From: Freddie Cash <fjwcash@gmail.com> To: Chris Stankevitz <chris@stankevitz.com> Cc: FreeBSD Filesystems <freebsd-fs@freebsd.org> Subject: Re: Offline/online a drive from a mounted RW RAIDZx pool: resilver needed? Message-ID: <CAOjFWZ5V2DdKfsDcFrtrwOKNpx4=UDGEcWEj5%2BYpbYkHw05qZg@mail.gmail.com> In-Reply-To: <55A53BE2.7060609@stankevitz.com> References: <55A4461F.6020308@stankevitz.com> <CAOjFWZ6vuxtCy01ro=oHKvZPpKi6BbaAhtWZk%2B6gDk9aPdTy%2Bw@mail.gmail.com> <55A53BE2.7060609@stankevitz.com>
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On Tue, Jul 14, 2015 at 9:42 AM, Chris Stankevitz <chris@stankevitz.com> wrote: > On 7/13/15 4:26 PM, Freddie Cash wrote: > >> If you don't write anything to the pool, or at least, nothing gets >> written to that vdev, then there's >> > > Freddie, > > I missed part of your message. Are you saying that there are two > possibilities in the offline/online scenario: the drive comes online > immediately (no missed writes) or the drive undergoes a complete resilver > (1 or more missing bytes)? > =E2=80=8BSorry, was typing that on my phone, and meant to hit back not send= . If nothing is written to the pool (or, at least that specific vdev) while the drive is removed, then the metadata on the drive will match the pool, and it can be onlined without a resilver. If only a little bit of data has been written, and a short bit of time has passed, =E2=80=8B =E2=80=8Bthen the drive will only need to sync (resilver) that changed data= to the drive. If a lot of data has been written, or a long time has passed (not sure what qualifies as "long", maybe until the last txg synced to the disk is no longer in the txg history of the pool?), then the entire drive will be resilvered. Or, something along those lines. That's what I've observed by doing various tests (offline drive, pull drive, write to pool, online drive; or offline drive, replace with new one, start resilver, new drive dies, stick in old drive, online it, wait for resilver; and other scenarios). =E2=80=8B --=20 Freddie Cash fjwcash@gmail.com
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