Re: Best way to create RAID-6 for swap partition - existing one failed
From: Stan Hoeppner <hidden>
Date: 2011-05-18 21:53:39
On 5/18/2011 3:13 PM, Gavin Flower wrote:
quoted hunk ↗ jump to hunk
--- On Thu, 19/5/11, Stan Hoeppner <stan@hardwarefreak.com> wrote:quoted
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 partitionfailed. 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. -- StanThanks. 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.) 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