Very slow writing to SATA disk

[Mikhail T.]

Hi!

I've got a new Hitachi drive with 16Mb of cache:

	ad8: 476940MB <HDS725050KLA360 K2AOA11A> at ata4-master SATA150

and am trying to use it to store backups online. Unfortunately, writing
to the disk is painfully slow (by today's standards) -- it can barely
keep 7Mb/second and my other (SCSI) disks run circles around it.

I tried to just cp a huge file from a SCSI disk to this one -- without
any other activity. 7Mb/second is the best it could do :-(

For bulk writing, undisturbed by other access, I'd expect at least
30Mb/sec... Is it the drive, the controller:

	atapci1: <SiI 3114 SATA150 controller> port 0xac00-0xac07,0xa480-0xa483,0xa400-0xa407,0xa080-0xa083,0xa000-0xa00f mem 0xbe6fbc00-0xbe6fbfff irq 25 at device 5.0 on pci3

the driver (6.0/amd64), or a misconfiguration of some sort?

According to smartctl, the drive runs at 56C during the copying. Its
idle temperature seems to be 54C.

Thanks for any hints!

	-mi