--- On Thu, 19/5/11, Stan Hoeppner <stan@hardwarefreak.com> wrote:

From: Stan Hoeppner <redacted>
Subject: Re: Best way to create RAID-6 for swap partition - existing one failed
To: "Gavin Flower" <redacted>
Cc: linux-raid@vger.kernel.org, neilb@suse.de, mb@gem.win.co.nz
Date: Thursday, 19 May, 2011, 6:59
On 5/16/2011 4:41 PM, Gavin Flower
wrote:

quoted

Motivation, existing RAID-6 swap partition

failed.  I am thinking I should recreate it in a new
format, as currently it is 'Version : 0.90', rather than
simply rebuild it.
<snip>

Forget using a partition.  Simply use a swap
file.  This example creates
a 1GB swap file in the / filesystem.  You can locate
it on any
filesystem you wish.

# swappoff -a
# dd if=/dev/zero of=/swapfile1 bs=1024 count=1048576
# mkswap /swapfile1
# swapon /swapfile1
# vi /etc/fstab
Add:
/swapfile1 swap swap defaults 0 0

and remove your old entry for the failed swap partition.

There is little performance difference between swap files
and swap
partitions with modern kernels.  The kernel will map
the disk location
of the swap file and perform direct disk access, bypassing
the
filesystem and buffer cache.

-- 
Stan

Okay Stan,

What obvious thing have I done, or not done, here?

What should I do now?

(I am not panicking, because I can always revert back...)

I tried to implement you suggestion, 

# swapoff -a
# dd if=/dev/zero of=/swapfile1 bs=1K count=16M
16777216+0 records in
16777216+0 records out
17179869184 bytes (17 GB) copied, 119.642 s, 144 MB/s
# mkswap /swapfile1
Setting up swapspace version 1, size = 16777212 KiB
no label, UUID=9afbf206-9a79-45b8-ad4b-148f71c440d7
# swapon /swapfile1
# cp /etc/fstab /etc/fstab-20110519

in
/etc/fstab
I replaced
UUID=654f3b90-ed2c-4de6-9f2a-e2ad65fd1af1 swap                    swap    defaults        0 0
by
/swapfile1                                swap                    swap    defaults        0 0

The log message for the swapon was:
May 19 11:27:38 saturn kernel: [38075.451398] Adding 16777212k swap on /swapfile1.  Priority:-1 extents:159 across:24068092k 


However, it failed to hibernate.  The log messages were:
May 19 11:44:43 saturn kernel: [39043.115385] sd 1:0:0:0: [sdb] Starting disk
May 19 11:44:43 saturn kernel: [39043.128453] sd 2:0:0:0: [sdc] Starting disk
May 19 11:44:43 saturn kernel: [39043.140116] sd 3:0:0:0: [sdd] Starting disk
May 19 11:44:43 saturn kernel: [39043.150889] sd 5:0:0:0: [sde] Starting disk
May 19 11:44:43 saturn kernel: [39043.165729] PM: thaw of devices complete after 756.642 msecs
May 19 11:44:43 saturn kernel: [39043.322491] PM: Saving image data pages (809839 pages) ... done
May 19 11:44:43 saturn kernel: [39094.461575] PM: Wrote 3239356 kbytes in 51.13 seconds (63.35 MB/s)
May 19 11:44:43 saturn kernel: [39094.465739] PM: S
May 19 11:44:43 saturn kernel: [39094.482407] PM: Swap header not found!
May 19 11:44:43 saturn kernel: [39094.485188] |
May 19 11:44:43 saturn kernel: [39094.706731] Restarting tasks ... done.
May 19 11:44:43 saturn NetworkManager[1501]: <info> wake requested (sleeping: yes  enabled: yes)
May 19 11:44:43 saturn NetworkManager[1501]: <info> waking up and re-enabling...
May 19 11:44:43 saturn NetworkManager[1501]: <info> (eth0): now managed
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