[mythtv-users] SATA drive speeds

[Allan Wilson]

I have a PIV 3.0 GHz system for my  backend that has a hard time plalying
back HD content especially when other things are going on. I know this is
the low end of what it takes to run HD using the processor but reading some
older posts I came back to the subject of dma and sata support for that
feature in the linux kernel. Can you set dma on a sata device? What kind of
speeds should I be getting out of my sata drives? I have the Intel ICH5
chipset. Running the following commands I get:

sudo hdparm -d1 /dev/sda
/dev/sda:
 settign using_dma to 1 (on)
 HDIO_SET_DMA failed: Inappropriate ioctl for device

and for a speed test I got:

sudo hdparm -tT /dev/sda
/dev/sda:
 Timing cached reads:   2604 MB in  2.00 seconds = 1300.90 MB/sec
 Timing buffered disk reads:  176 MB in  3.02 seconds =  58.29 MB/sec
/dev/sdb:
 Timing cached reads:   2576 MB in  2.00 seconds = 1287.55 MB/sec
 Timing buffered disk reads:  180 MB in  3.01 seconds =  59.85 MB/sec
/dev/sdc:
 Timing cached reads:   2588 MB in  2.00 seconds = 1293.55 MB/sec
 Timing buffered disk reads:  190 MB in  3.02 seconds =  62.99 MB/sec

This speed is pretty constant and I wasn't really doing anything on the hard
drive when I ran the tests.

I have the following three sata drives:

allan at mythtv:/proc/scsi$ more scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: HDS722516VLSA80  Rev: V34O
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi1 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: Maxtor 6B300S0   Rev: BANC
  Type:   Direct-Access                    ANSI SCSI revision: 05
Host: scsi3 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: WDC WD3200JD-22K Rev: 08.0
  Type:   Direct-Access                    ANSI SCSI revision: 05

I don't know enough about this but my question is: Are my hard drives
slowing my system down? Thanks for the help.

Allan
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