--- On Thu, 19/5/11, Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx> wrote: > From: Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx> > Subject: Re: Best way to create RAID-6 for swap partition - existing one failed > To: "Gavin Flower" <gavinflower@xxxxxxxxx> > Cc: linux-raid@xxxxxxxxxxxxxxx, neilb@xxxxxxx, mb@xxxxxxxxxxxxx > Date: Thursday, 19 May, 2011, 9:53 > On 5/18/2011 3:13 PM, Gavin Flower > wrote: > > --- On Thu, 19/5/11, Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx> > wrote: > > > >> From: Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx> > >> Subject: Re: Best way to create RAID-6 for swap > partition - existing one failed > >> To: "Gavin Flower" <gavinflower@xxxxxxxxx> > >> Cc: linux-raid@xxxxxxxxxxxxxxx, > neilb@xxxxxxx, mb@xxxxxxxxxxxxx > >> Date: Thursday, 19 May, 2011, 6:59 > >> On 5/16/2011 4:41 PM, Gavin Flower > >> wrote: > >> > >>> 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 > >> > > > > 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.) > > > > 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. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
