Date: Fri, 16 Aug 2013 08:49:40 -0500 From: dweimer <dweimer@dweimer.net> To: freebsd-questions@freebsd.org Subject: Re: ZFS Snapshots Not able to be accessed under .zfs/snapshot/name Message-ID: <23413f3a4b95328c0bc838e6ffad364d@dweimer.net> In-Reply-To: <776e30b627bf30ece7545e28b2a2e064@dweimer.net> References: <22a7343f4573d6faac5aec1d7c9a1135@dweimer.net> <520C405A.6000408@ShaneWare.Biz> <776e30b627bf30ece7545e28b2a2e064@dweimer.net>
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On 08/15/2013 10:00 am, dweimer wrote:
> On 08/14/2013 9:43 pm, Shane Ambler wrote:
>> On 14/08/2013 22:57, dweimer wrote:
>>> I have a few systems running on ZFS with a backup script that creates
>>> snapshots, then backs up the .zfs/snapshot/name directory to make
>>> sure
>>> open files are not missed. This has been working great but all of
>>> the
>>> sudden one of my systems has stopped working. It takes the snapshots
>>> fine, zfs list -t spnapshot shows the snapshots, but if you do an ls
>>> command, on the .zfs/snapshot/ directory it returns not a directory.
>>>
>>> part of the zfs list output:
>>>
>>> NAME USED AVAIL REFER MOUNTPOINT
>>> zroot 4.48G 29.7G 31K none
>>> zroot/ROOT 2.92G 29.7G 31K none
>>> zroot/ROOT/91p5-20130812 2.92G 29.7G 2.92G legacy
>>> zroot/home 144K 29.7G 122K /home
>>>
>>> part of the zfs list -t snapshot output:
>>>
>>> NAME USED AVAIL REFER
>>> MOUNTPOINT
>>> zroot/ROOT/91p5-20130812@91p5-20130812--bsnap 340K - 2.92G -
>>> zroot/home@home--bsnap 22K - 122K -
>>>
>>> ls /.zfs/snapshot/91p5-20130812--bsnap/
>>> Does work at the right now, since the last reboot, but wasn't always
>>> working, this is my boot environment.
>>>
>>> if I do ls /home/.zfs/snapshot/, result is:
>>> ls: /home/.zfs/snapshot/: Not a directory
>>>
>>> if I do ls /home/.zfs, result is:
>>> ls: snapshot: Bad file descriptor
>>> shares
>>>
>>> I have tried zpool scrub zroot, no errors were found, if I reboot the
>>> system I can get one good backup, then I start having problems.
>>> Anyone
>>> else ever ran into this, any suggestions as to a fix?
>>>
>>> System is running FreeBSD 9.1-RELEASE-p5 #1 r253764: Mon Jul 29
>>> 15:07:35
>>> CDT 2013, zpool is running version 28, zfs is running version 5
>>>
>>
>>
>> I can say I've had this problem. Not certain what fixed it. I do
>> remember I decided to stop snapshoting if I couldn't access them and
>> deleted existing snapshots. I later restarted the machine before I
>> went back for another look and they were working.
>>
>> So my guess is a restart without existing snapshots may be the key.
>>
>> Now if only we could find out what started the issue so we can stop it
>> happening again.
>
> I had actually rebooted it last night, prior to seeing this message, I
> do know it didn't have any snapshots this time. As I am booting from
> ZFS using boot environments I may have had an older boot environment
> still on the system the last time it was rebooted. Backups ran great
> last night after the reboot, and I was able to kick off my pre-backup
> job and access all the snapshots today. Hopefully it doesn't come
> back, but if it does I will see if I can find anything else wrong.
>
> FYI,
> It didn't shutdown cleanly, so if this helps anyone find the issue,
> this is from my system logs:
> Aug 14 22:08:04 cblproxy1 kernel:
> Aug 14 22:08:04 cblproxy1 kernel: Fatal trap 12: page fault while in
> kernel mode
> Aug 14 22:08:04 cblproxy1 kernel: cpuid = 0; apic id = 00
> Aug 14 22:08:04 cblproxy1 kernel: fault virtual address = 0xa8
> Aug 14 22:08:04 cblproxy1 kernel: fault code = supervisor
> write data, page not present
> Aug 14 22:08:04 cblproxy1 kernel: instruction pointer =
> 0x20:0xffffffff808b0562
> Aug 14 22:08:04 cblproxy1 kernel: stack pointer =
> 0x28:0xffffff80002238f0
> Aug 14 22:08:04 cblproxy1 kernel: frame pointer =
> 0x28:0xffffff8000223910
> Aug 14 22:08:04 cblproxy1 kernel: code segment = base 0x0,
> limit 0xfffff, type 0x1b
> Aug 14 22:08:04 cblproxy1 kernel: = DPL 0, pres 1, long 1, def32 0,
> gran 1
> Aug 14 22:08:04 cblproxy1 kernel: processor eflags = interrupt
> enabled, resume, IOPL = 0
> Aug 14 22:08:04 cblproxy1 kernel: current process = 1
> (init)
> Aug 14 22:08:04 cblproxy1 kernel: trap number = 12
> Aug 14 22:08:04 cblproxy1 kernel: panic: page fault
> Aug 14 22:08:04 cblproxy1 kernel: cpuid = 0
> Aug 14 22:08:04 cblproxy1 kernel: KDB: stack backtrace:
> Aug 14 22:08:04 cblproxy1 kernel: #0 0xffffffff808ddaf0 at
> kdb_backtrace+0x60
> Aug 14 22:08:04 cblproxy1 kernel: #1 0xffffffff808a951d at panic+0x1fd
> Aug 14 22:08:04 cblproxy1 kernel: #2 0xffffffff80b81578 at
> trap_fatal+0x388
> Aug 14 22:08:04 cblproxy1 kernel: #3 0xffffffff80b81836 at
> trap_pfault+0x2a6
> Aug 14 22:08:04 cblproxy1 kernel: #4 0xffffffff80b80ea1 at trap+0x2a1
> Aug 14 22:08:04 cblproxy1 kernel: #5 0xffffffff80b6c7b3 at calltrap+0x8
> Aug 14 22:08:04 cblproxy1 kernel: #6 0xffffffff815276da at
> zfsctl_umount_snapshots+0x8a
> Aug 14 22:08:04 cblproxy1 kernel: #7 0xffffffff81536766 at
> zfs_umount+0x76
> Aug 14 22:08:04 cblproxy1 kernel: #8 0xffffffff809340bc at
> dounmount+0x3cc
> Aug 14 22:08:04 cblproxy1 kernel: #9 0xffffffff8093c101 at
> vfs_unmountall+0x71
> Aug 14 22:08:04 cblproxy1 kernel: #10 0xffffffff808a8eae at
> kern_reboot+0x4ee
> Aug 14 22:08:04 cblproxy1 kernel: #11 0xffffffff808a89c0 at
> kern_reboot+0
> Aug 14 22:08:04 cblproxy1 kernel: #12 0xffffffff80b81dab at
> amd64_syscall+0x29b
> Aug 14 22:08:04 cblproxy1 kernel: #13 0xffffffff80b6ca9b at
> Xfast_syscall+0xfb
Well its back, 3 of the 8 file systems I am taking snapshots of failed
in last nights backups.
The only thing different on this system from all the 4 others I have
running is that it has a second disk volume with a UFS file system.
Setup is 2 Disks, both setup with GPART:
=> 34 83886013 da0 GPT (40G)
34 256 1 boot0 (128k)
290 10485760 2 swap0 (5.0G)
10486050 73399997 3 zroot0 (35G)
=> 34 41942973 da1 GPT (20G)
34 41942973 1 squid1 (20G)
I didn't want the Squid cache directory on ZFS, system is running on an
ESX 4.1 server backed by iSCSI SAN. I have 4 other servers running on
the same group of ESX servers and SAN, booting from ZFS without this
problem. Two of the other 4 are also running Squid but forward to this
one so they are running without a local disk cache.
--
Thanks,
Dean E. Weimer
http://www.dweimer.net/
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