On 20:48 20 Jul 2004, kalin mintchev <kalin@xxxxxx> wrote: | i want to add a swap file to my system. following the rule of 2 to 1 the | file would need to be 2 gigs because the ram is a gig. but using the dd | command what do i put for bs and count? | i was looking around on google but couldn't exactly find it.. block size * count should equal your swap file size. You want count to be "small". So: % dc 1024 1024 *p 1048576 % dd if=/dev/zero count=1024 bs=1048576 of=your-swap-file % In fact, you can probably do it in a single write: % dc 1024 1024 1024 **p 1073741824 % dd if=/dev/zero count=1 bs=1073741824 of=your-swap=-file I just did that on a machine here and it took quite a while. That may be because a big block size will map a chunk of memory, virtually, and as you fill it from /dev/zero that will cycle your RAM to swap as things fill. So probably you want a big blocksize, but not as big as possible. One megabyte should do nicely - big enough to move a lot of data per write, small enough that its memory footprint doesn't blow your RAM usage. The basic deal is that small block size and large count means lots of write() calls, and that is inefficiency because each such call has some overhead; to minimise that you minimise count and maximise blocksize without getting silly. Cheers, -- Cameron Simpson <cs@xxxxxxxxxx> DoD#743 http://www.cskk.ezoshosting.com/cs/ The problem is, every time something goes wrong, the paperwork is found in order... - Walker on NASA -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
