On Wed, Aug 20, 2003 at 11:21:49AM -0400, Eric Sproul wrote:
> Hi all,
> I am having a problem with disk I/O on a new holdingdisk I installed in
> my AMANDA server.  The server had previously been exclusively SCSI, and
> I had no problems.  When we broke down an old server, I snagged a 60GB
> IDE drive (an IBM Deskstar 75GXP) to use as cheap extra holding disk
> space-- "free" as opposed to ~$450 for a similar-sized SCSI drive.  The
> problem is, the read throughput is terrible and it's causing backups to
> run about twice as long, due to taper not being able to extract stuff
> off the holding disk fast enough.
> 
> The AMANDA server is PC-based, with Tyan Thunder 100 (S1836) mobo and
> the i440GX chipset (PIIX4 integrated IDE controller).  According to the
> manual, the IDE controller should do up to ATA/33 (UDMA mode 2, I
> believe).  It's running Debian testing/unstable, with kernel 2.4.21.
> 
> Anyway, I plug the drive up, setting the BIOS to auto-everything for IDE
> disks.  I see the disk come up and get recognized.  However, when the
> kernel detects the IDE disk, it reports no UDMA setting, leading me to
> believe it came up in one of the older PIO modes.  This is confirmed
> with a quick hdparm test that shows an abysmal 4.5 MB/s buffered disk
> read speed.  By comparison, the same disk at UDMA(33) in a similar
> machine reports 28 MB/s.
> 
> Does anyone here have experience with IDE and DMA under recent Linux
> kernels?  Anyone else have a problem like this?  I figured the
> integrated controller on a 440GX board would have no compatibility
> problems, as it's extremely common.  Maybe I'm wrong.

Not linux, but Solaris.  I'm also on a 440 board, but I think BX.

I have two SCSI disks and a chunk of each used for holding disk.
I also have a larger IDE disk and used to use a chunk of that for
holding disk too.  But it proved too low performing so I dropped it
except for storage of static data.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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