--- 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, 9:53
On 5/18/2011 3:13 PM, Gavin Flower
wrote:

quoted

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

wrote:

quoted

quoted

From: Stan Hoeppner <redacted>
Subject: Re: Best way to create RAID-6 for swap

partition - existing one failed

quoted

quoted

To: "Gavin Flower" <redacted>
Cc: linux-raid@vger.kernel.org,

neilb@suse.de, mb@gem.win.co.nz

quoted

quoted

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

quoted

quoted

format, as currently it is 'Version : 0.90',

rather than

quoted

quoted

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

quoted

quoted

it on any
filesystem you wish.

# swappoff -a
# dd if=/dev/zero of=/swapfile1 bs=1024

count=1048576

quoted

quoted

# mkswap /swapfile1
# swapon /swapfile1
# vi /etc/fstab
Add:
/swapfile1 swap swap defaults 0 0

and remove your old entry for the failed swap

partition.

quoted

quoted

There is little performance difference between

swap files

quoted

quoted

and swap
partitions with modern kernels.  The kernel

will map

quoted

quoted

the disk location
of the swap file and perform direct disk access,

bypassing

quoted

quoted

the
filesystem and buffer cache.

-- 
Stan

Thanks.

Interesting!

(Reminds me of when I first got into Linux.  Then

you could have any size swap file up to 128 MB, and have up
to 8 swap files, for a maximum of 1 GB. I then had about 64
MB of RAM - now I have 8 GB of RAM. Also, swap partitions
were recommended.  When the 2.4 kernel first came out,
it was said to be faster if you had at least 16 MB.)

quoted

I read up and could not see any benefit in changing,

so I ended up 'simply' reassembling the partition.

The big benefits are flexibility, simplicity, and time
consumed.  Given
your particular case it seems a bit ironic that you see no
benefit in
using swap files.  The time to resolution in this case
would be mere
seconds with swap files.  How much total time did you
spend reassembling
your swap partition, bot command execution time, but your
total time?

-- 
Stan

I took longer than I'm prepared to admit!  :-)

I'll take note, and either apply your idea next time it happens, or when I do a major O/S upgrade.


Thanks.

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