[plug] Hdparm

[Craig Ringer]

> IBM PC330 - Dual PII 400 - IBM ServeRAID/Adaptec UWSCSI-3 (Raid 5)
> 
> /dev/sda1:
>  Timing buffer-cache reads:   128 MB in  3.12 seconds = 41.03 MB/sec
>  Timing buffered disk reads:  64 MB in  7.82 seconds =  8.18 MB/sec

Dual P4 Xeon 2.4GHz, 2G RAM, 3ware Escalade 8500-8 in RAID 1 across 
2x80g Seagate Barracuda SATA Vs:

# hdparm -tT /dev/sda
/dev/sda:
  Timing buffer-cache reads:   128 MB in  0.30 seconds =422.84 MB/sec
  Timing buffered disk reads:  64 MB in  1.69 seconds = 37.88 MB/sec

And in RAID 5 across 3x120g Seagate Barracuda SATA Vs:

# hdparm -tT /dev/sdb
/dev/sdb:
  Timing buffer-cache reads:   128 MB in  0.30 seconds =431.19 MB/sec
  Timing buffered disk reads:  64 MB in  1.04 seconds = 61.71 MB/sec

*gloat*

That said, bonnie++ benchmarks are much more useful, hdparm doesn't 
really tell you much about real world performance.

Craig Ringer