thank you for the explanation. it helps... > 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 > -- Software is like sex: It's better when it's free. (Linus Torvalds) -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
