On 6/25/05, Allan Stirling <[EMAIL PROTECTED]> wrote: > Kelly wrote: > > Think I've found a source of my constant crashing. I have a Maxtor > > SATA 250GB drive. I started poking around google and came up with the > > hdparm test. I ran it and got > > > > Timing cached reads: 816 MB in 2.01 seconds > > > > A respectable IDE drive and do 3000mb in 2.00 seconds. > > > > So my drive is running at 20% efficiency. That will make a difference. > > > Ummm... No. You're reading the results wrongly, I'm afraid :) > I would seriously doubt you'd see 1.5Gb / sec outside the datacentre. > 150Mb / sec... _maybe_. > > Cached reads are just that - It reads the same sector over and over. > This means it's already in drive's read cache. So what you're seeing > here is the transfer rate from the controller without (much) SATA > latency, no seek latency, no rotational latency. That's not the test you > want. You want 'buffered disk reads'. This is the (almost real) raw > performance of the drive. > > Here's the results from my array, which is a 8 disk RAID5, spread over 2 > SATA controllers on a PCI-X dual Xeon (yes, I believe overkill _is_ just > a word): > > hdparm -Tt /dev/sda > > /dev/sda: > Timing cached reads: 2204 MB in 2.00 seconds = 1101.07 MB/sec > Timing buffered disk reads: 374 MB in 3.01 seconds = 124.31 MB/sec > > The 'buffered disk reads' is the line you're looking for. And 124Mb / > sec is quite good for this type of setup. > > Cheers, > > Allan.
My output hdparm -Tt /dev/sda /dev/sda: Timing cached reads: 968 MB in 2.00 seconds = 483.83 MB/sec HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate ioctl for device Timing buffered disk reads: 152 MB in 3.05 seconds = 49.81 MB/sec HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate ioctl for device _______________________________________________ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users