On Jul 28, 2010, at 4:11 PM, Robert Milkowski wrote:
>
> fyi
This covers the case where an exported pool has lost its log.
zpool export
[log disk or all disks in a mirrored log disappear]
zpool import -- currently fails, missing top-level vdev
The following cases are already recoverable:
If the pool is not exported and the log disappears, then the pool
can import ok if the zpool.cache file is current.
*crash*
[log disk or all disks in a mirrored log disappear]
zpool import -- succeeds, pool state is updated
keep on truckin'
If the log device fails while the pool is imported, then the pool
marks the device as failed.
[log disk or all disks in a mirrored log disappear]
report error, change pool state to show failed log device
keep on truckin'
-- richard
>
> --
> Robert Milkowski
> http://milek.blogspot.com
>
>
> -------- Original Message --------
> Subject: zpool import despite missing log [PSARC/2010/292 Self Review]
> Date: Mon, 26 Jul 2010 08:38:22 -0600
> From: Tim Haley <tim.ha...@oracle.com>
> To: psarc-...@sun.com
> CC: zfs-t...@sun.com
>
> I am sponsoring the following case for George Wilson. Requested binding
> is micro/patch. Since this is a straight-forward addition of a command
> line option, I think itqualifies for self review. If an ARC member
> disagrees, let me know and I'll convert to a fast-track.
>
> Template Version: @(#)sac_nextcase 1.70 03/30/10 SMI
> This information is Copyright (c) 2010, Oracle and/or its affiliates.
> All rights reserved.
> 1. Introduction
> 1.1. Project/Component Working Name:
> zpool import despite missing log
> 1.2. Name of Document Author/Supplier:
> Author: George Wilson
> 1.3 Date of This Document:
> 26 July, 2010
>
> 4. Technical Description
>
> OVERVIEW:
>
> ZFS maintains a GUID (global unique identifier) on each device and
> the sum of all GUIDs of a pool are stored into the ZFS uberblock.
> This sum is used to determine the availability of all vdevs
> within a pool when a pool is imported or opened. Pools which
> contain a separate intent log device (e.g. a slog) will fail to
> import when that device is removed or is otherwise unavailable.
> This proposal aims to address this particular issue.
>
> PROPOSED SOLUTION:
>
> This fast-track introduce a new command line flag to the
> 'zpool import' sub-command. This new option, '-m', allows
> pools to import even when a log device is missing. The contents
> of that log device are obviously discarded and the pool will
> operate as if the log device were offlined.
>
> MANPAGE DIFFS:
>
> zpool import [-o mntopts] [-p property=value] ... [-d dir | -c
> cachefile]
> - [-D] [-f] [-R root] [-n] [-F] -a
> + [-D] [-f] [-m] [-R root] [-n] [-F] -a
>
>
> zpool import [-o mntopts] [-o property=value] ... [-d dir | -c
> cachefile]
> - [-D] [-f] [-R root] [-n] [-F] pool |id [newpool]
> + [-D] [-f] [-m] [-R root] [-n] [-F] pool |id [newpool]
>
> zpool import [-o mntopts] [ -o property=value] ... [-d dir |
> - -c cachefile] [-D] [-f] [-n] [-F] [-R root] -a
> + -c cachefile] [-D] [-f] [-m] [-n] [-F] [-R root] -a
>
> Imports all pools found in the search directories.
> Identical to the previous command, except that all pools
>
> + -m
> +
> + Allows a pool to import when there is a missing log device
>
> EXAMPLES:
>
> 1). Configuration with a single intent log device:
>
> # zpool status tank
> pool: tank
> state: ONLINE
> scan: none requested
> config:
>
> NAME STATE READ WRITE CKSUM
> tank ONLINE 0 0 0
> c7t0d0 ONLINE 0 0 0
> logs
> c5t0d0 ONLINE 0 0 0
>
> errors: No known data errors
>
> # zpool import tank
> The devices below are missing, use '-m' to import the pool anyway:
> c5t0d0 [log]
>
> cannot import 'tank': one or more devices is currently unavailable
>
> # zpool import -m tank
> # zpool status tank
> pool: tank
> state: DEGRADED
> status: One or more devices could not be opened. Sufficient replicas
> exist for
> the pool to continue functioning in a degraded state.
> action: Attach the missing device and online it using 'zpool online'.
> see:
> http://www.sun.com/msg/ZFS-8000-2Q
>
> scan: none requested
> config:
>
> NAME STATE READ WRITE CKSUM
> tank DEGRADED 0 0 0
> c7t0d0 ONLINE 0 0 0
> logs
> 1693927398582730352 UNAVAIL 0 0 0 was
> /dev/dsk/c5t0d0
>
> errors: No known data errors
>
> 2). Configuration with mirrored intent log device:
>
> # zpool add tank log mirror c5t0d0 c5t1d0
> zr...@diskmonster:/dev/dsk# zpool status tank
> pool: tank
> state: ONLINE
> scan: none requested
> config:
>
> NAME STATE READ WRITE CKSUM
> tank ONLINE 0 0 0
> c7t0d0 ONLINE 0 0 0
> logs
> mirror-1 ONLINE 0 0 0
> c5t0d0 ONLINE 0 0 0
> c5t1d0 ONLINE 0 0 0
>
> errors: No known data errors
>
> # zpool import 429789444028972405
> The devices below are missing, use '-m' to import the pool anyway:
> mirror-1 [log]
> c5t0d0
> c5t1d0
>
> # zpool import -m tank
> # zpool status tank
> pool: tank
> state: DEGRADED
> status: One or more devices could not be opened. Sufficient replicas
> exist for
> the pool to continue functioning in a degraded state.
> action: Attach the missing device and online it using 'zpool online'.
> see:
> http://www.sun.com/msg/ZFS-8000-2Q
>
> scan: none requested
> config:
>
> NAME STATE READ WRITE CKSUM
> tank DEGRADED 0 0 0
> c7t0d0 ONLINE 0 0 0
> logs
> mirror-1 UNAVAIL 0 0 0
> insufficient replicas
> 46385995713041169 UNAVAIL 0 0 0 was
> /dev/dsk/c5t0d0
> 13821442324672734438 UNAVAIL 0 0 0 was
> /dev/dsk/c5t1d0
>
> errors: No known data errors
>
> 6. Resources and Schedule
> 6.4. Steering Committee requested information
> 6.4.1. Consolidation C-team Name:
> ON
> 6.5. ARC review type: Automatic
> 6.6. ARC Exposure: open
>
> _______________________________________________
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>
> opensolaris-...@opensolaris.org
>
>
>
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--
Richard Elling
rich...@nexenta.com +1-760-896-4422
Enterprise class storage for everyone
www.nexenta.com
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