[K12OSN] new server serial ATA or SCSI

[Sudev Barar]

On Thu, 2004-02-19 at 22:46, Chris Kacoroski wrote:
> This may be a bit late, but I have ordered a server with 2TB of SATA 
> drives hooked into a single 3ware card.  I will run some tests when I 
> get it (should be a few weeks) and post them.
I am running three servers all using same Intel865 motherboard (if it
makes any difference - two of the with 2 gig RAM and one with 1.5 gig)
The result of hdparm are below.
I could not make out why variation in timing for /dev/mdo and /dev/md1
made across the same two scsi drives in second server. Nor could I make
out the difference in timings returned from IDE drives on third server
as both are of the same specs.
What can I make out of all this? In future what combination to
recommend? I feel for cost effectiveness SATA drives may be actually the
best.
Comments?

Timing from $hdparm -tT:

Server one: One SATA drive
/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.28 seconds =457.14 MB/sec
 Timing buffered disk reads:  64 MB in  1.68 seconds = 38.10 MB/sec

Server two: Two SCSI drives in raid0 array
/dev/md0:
 Timing buffer-cache reads:   128 MB in  0.24 seconds =533.33 MB/sec
 Timing buffered disk reads:  64 MB in  1.33 seconds = 48.12 MB/sec

/dev/md1:
 Timing buffer-cache reads:   128 MB in  0.24 seconds =533.33 MB/sec
 Timing buffered disk reads:  64 MB in  0.62 seconds = 103.23 MB/sec

/dev/sda:
 Timing buffer-cache reads:   128 MB in  0.23 seconds =556.52 MB/sec
 Timing buffered disk reads:  64 MB in  0.99 seconds = 64.65 MB/sec

/dev/sdb:
 Timing buffer-cache reads:   128 MB in  0.24 seconds =556.52 MB/sec
 Timing buffered disk reads:  64 MB in  0.97 seconds = 65.98 MB/sec

Server three: Two IDE drives in raid0 array
/dev/md0:
 Timing buffer-cache reads:   128 MB in  0.54 seconds =237.04 MB/sec
 Timing buffered disk reads:  64 MB in  1.65 seconds = 38.79 MB/sec
 
/dev/md1:
 Timing buffer-cache reads:   128 MB in  0.53 seconds =241.51 MB/sec
 Timing buffered disk reads:  64 MB in  1.63 seconds = 39.26 MB/sec

/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.56 seconds =228.57 MB/sec
 Timing buffered disk reads:  64 MB in  1.23 seconds = 52.03 MB/sec
 
/dev/hdc:
 Timing buffer-cache reads:   128 MB in  0.58 seconds =220.69 MB/sec
 Timing buffered disk reads:  64 MB in  2.26 seconds = 28.32 MB/sec


-- 
Sudev Barar

Learning Linux