hd spin down
 

hy,

i have a problem with spinning down my harddisk. I entered hdparm -s 1 /dev/hda. After five seconds the hd spins down. i takes 30 sec up to 2 minutes the hd starts again. Why doesn't the harddisk stay in suspend mode?

to reduce the tasks linux entered the runlevel 1. After that i entered ps -A and get the following tasks:

PID TTY TIME CMD
1 ? 00:00:04 init
2 ? 00:00:00 migration/0
3 ? 00:00:00 ksoftirqd/0
4 ? 00:00:00 events/0
5 ? 00:00:00 khelper
6 ? 00:00:00 kacpid
34 ? 00:00:00 kblockd/0
46 ? 00:00:00 pdflush
47 ? 00:00:00 pdflush
49 ? 00:00:00 aio/0
48 ? 00:00:00 kswapd0
141 ? 00:00:00 ata/0
144 ? 00:00:00 kseriod
200 ? 00:00:00 kjournald
388 ? 00:00:00 khubd
524 ? 00:00:00 khpsbpkt
958 ? 00:00:00 automount
1427 tty1 00:00:00 getty
1672 ? 00:00:00 sshd
1675 pts/0 00:00:00 bash
1846 pts/0 00:00:00 ps

what should i do to let the harddisk stay in suspend mode?

bye
Henning

Hard drives are designed for full on or full off. Putting them in suspend mode or sleep mode reduces their lifetime. You can put CD-ROM, ZIP, JAZ, Superdisk (LS-120), floppy dirves, sound cards, NICS, modems, video cards, capture card in sleep or suspend mode if you need to save power.

Probably your flush interval is waking up the drives. You can run sync before putting your drives in suspend or sleep mode. Next turn off automount.

everytime the kernel flushes the buffers or some program likes to update something on the filesystem the drive will wake up. there are various tools to stop that. have a look at noflushd for ide and scsi-idle (needs a kernel-patch) for scsi-drives.
have a look into your /proc/sys/vm/ too. there (maybe) is a file called laptop_mode. if its there, write "1" to it to enable this mode. another file there is bdflush. there nr5 an nr6 are timings for writing "dirty" data to disk. they are seconds*100(Hz on i386). so raising these values will allow to delay writes too.

as electro allready mentioned your disk lifetime may get shorted by spinning the drive up and down all the time.
i like it on my servers to spin down the scsidrives and they are down for the night. on a laptop it's also quite handy to save some batterie. else i wouldn't recommend to use it.

sl mritch.