On Sunday 22 Jan 2006 18:07, Jack Malmostoso wrote: > Hello there list, > > I have noticed today that my AMD64 box has no swap! > I set it up during the installation as the /dev/md1 RAID-1 device, but > today I found out in free that swap=0: > > nostromo:~# free -m > total used free shared buffers cached > Mem: 1003 456 547 0 17 235 > -/+ buffers/cache: 203 800 > Swap: 0 0 0 > > So I tried to set it up manually: > > nostromo:~# mkswap -c /dev/sda2 > Setting up swapspace version 1, size = 509960 kB > no label, UUID=97b4cddf-1209-4c23-81f3-9deec9dd7c8a > nostromo:~# swapon /dev/sda2 > swapon: /dev/sda2: Invalid argument > > If I set up a swapfile, it works flawlessly: > > nostromo:~# dd if=/dev/zero of=pippo.swp bs=1024 count=10000 > 10000+0 records in > 10000+0 records out > 10240000 bytes (10 MB) copied, 0.121002 seconds, 84.6 MB/s > nostromo:~# mkswap -c pippo.swp 10000 > Setting up swapspace version 1, size = 10235 kB > no label, UUID=c46ec37b-360b-4bbc-a73b-bacac52b4562 > nostromo:~# swapon pippo.swp > > nostromo:~# free -m > total used free shared buffers cached > Mem: 1003 472 531 0 18 247 > -/+ buffers/cache: 206 797 > Swap: 9 0 9 > > > Any hints? I have added two swap entries in /etc/fstab but have not > rebooted yet to try them (work in progress :()... > > -- > Best Regards, Jack > Linux User #264449 > Powered by Debian GNU/Linux on AMD64
If you're using md for RAID-1, then the best way to have your swap partitions is to have one partition on each drive, *outside* the RAID array, and use them as separate swap partitions. There's little to no point in slowing down the system by RAIDing the contents of the swapfile -- under almost any circumstance in which that might be desirable, there will be worse and more immediate problems. With the kind of hardware RAID that appears as a single SCSI drive, you obviously can't avoid RAIDing swap; but at least it isn't such a performance hit. Due to the way the "modern" /dev works, you won't see an entry for sda2 at all if /dev/sda2 has already been appropriated by some RAID array. Check your /etc/raidtab to make sure that the partitions you want to use for swap really are available. Reboot, and run `swapon` manually to make sure it works. If it does, just add appropriate lines for /dev/sda2 and sdb2 to /etc/fstab and forget :) -- AJS delta echo bravo six four at earthshod dot co dot uk -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
