Date: Tue, 16 Jul 2013 14:55:04 -0700 From: javocado <javocado@gmail.com> To: Freddie Cash <fjwcash@gmail.com> Cc: FreeBSD Filesystems <freebsd-fs@freebsd.org> Subject: Re: ZFS memory exhaustion? Message-ID: <CAP1HOmSvyMUFp7jREodNRRS-vM-eabFOn-OCcmP8YpLaiJ0mRA@mail.gmail.com> In-Reply-To: <CAOjFWZ6JZsVPBByczELR2e9UNS6HdHLuU%2B1J544CmFLX77ZBfQ@mail.gmail.com> References: <CAP1HOmS6%2BMziqruTsdgvjYxHEb-B6Y05SCmgNomwHvtJTt-x6Q@mail.gmail.com> <CAOjFWZ6JZsVPBByczELR2e9UNS6HdHLuU%2B1J544CmFLX77ZBfQ@mail.gmail.com>
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Thank you. Is gstat the best way to watch zfs i/o ? On Tue, Jul 16, 2013 at 1:50 PM, Freddie Cash <fjwcash@gmail.com> wrote: > On Tue, Jul 16, 2013 at 1:26 PM, javocado <javocado@gmail.com> wrote: > >> I have a couple questions: >> >> - what does it look like when zfs needs more physical memory / is running >> out of memory for its operations? >> > > Disk I/O drops to 0, reading/writing any file from the pool appears to > "hang" the console, programs already loaded into RAM continue to work so > long as they don't touch the pool, etc. > > >> >> - what diagnostic numbers (vmstat, etc.) should I watch for that? >> >> Top output will show Wired at/near 100% of RAM. > > >> swapinfo shows zero (basically zero) swap usage, so it doesn't look like >> things get that bad. >> >> > ZFS uses non-swappable kernel memory, so you won't ever see swap used when > ZFS runs out of RAM. > > Those are the symptoms we've noticed when our ZFS systems have run out of > RAM. > > > -- > Freddie Cash > fjwcash@gmail.com >
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