Richard Scobie wrote:
> 3726/4726 work very well under high load with most drives. I guess
> you had some problem with the cage.
Does anyone have any performance figures to share, with these PMP
interfaces?
Hello,
what exactly you are looking for? For me it behaves exactly as
intended, and I did not notice any problems. When I communicate with
only one harddrive then performance is same as native. When I
communicate with more than one drive, then of course bandwidth between
host and PMP becomes bottleneck. /dev/sdf is using 1.5Gbps, everybody
else claims 3.0Gbps. Not that I see any difference :-(
Though I do not run any RAID on them (I would say that with PMP's
bottleneck it would be bad idea), so maybe I'm not stressing them
sufficiently to trip over bugs.
/dev/sda: 320GB Hitachi on sata_nv
/dev/sdb: 1TB Hitachi on sata_sil24 + 3726 (Sans Digital MS4UM)
/dev/sdc: 750GB Seagate on sata_sil24 + 3726
/dev/sdd: 1TB Hitachi on sata_sil24 + 3726
/dev/sde: 750GB Seagate on sata_sil24 + 3726
/dev/sdf: Sans Digital MS2UT with two 750GB in RAID1 on second sil24 port
gwy:~# for a in /dev/sd[abcdef]; do hdparm -t $a; done
/dev/sda:
Timing buffered disk reads: 214 MB in 3.01 seconds = 71.07 MB/sec
/dev/sdb:
Timing buffered disk reads: 236 MB in 3.00 seconds = 78.58 MB/sec
/dev/sdc:
Timing buffered disk reads: 220 MB in 3.02 seconds = 72.74 MB/sec
/dev/sdd:
Timing buffered disk reads: 240 MB in 3.02 seconds = 79.41 MB/sec
/dev/sde:
Timing buffered disk reads: 218 MB in 3.00 seconds = 72.64 MB/sec
/dev/sdf:
Timing buffered disk reads: 226 MB in 3.02 seconds = 74.95 MB/sec
Apparently 1TB Hitachis are slightly faster than 750GB Seagates...
gwy:~# hdparm -t /dev/sdb & hdparm -t /dev/sdd & sleep 20
(reformatted to show values in order, not interleaved)
/dev/sdd:
Timing buffered disk reads: 158 MB in 3.02 seconds = 52.40 MB/sec
/dev/sdb:
Timing buffered disk reads: 168 MB in 3.02 seconds = 55.68 MB/sec
gwy:~# hdparm -t /dev/sdc & hdparm -t /dev/sde & sleep 20
/dev/sde:
Timing buffered disk reads: 168 MB in 3.01 seconds = 55.89 MB/sec
/dev/sdc:
Timing buffered disk reads: 150 MB in 3.01 seconds = 49.77 MB/sec
gwy:~# hdparm -t /dev/sdb & hdparm -t /dev/sdc & hdparm -t /dev/sdd &
hdparm -t /dev/sde & sleep 20
/dev/sde:
Timing buffered disk reads: 98 MB in 3.02 seconds = 32.46 MB/sec
/dev/sdd:
Timing buffered disk reads: 100 MB in 3.06 seconds = 32.73 MB/sec
/dev/sdc:
Timing buffered disk reads: 92 MB in 3.07 seconds = 30.01 MB/sec
/dev/sdb:
Timing buffered disk reads: 118 MB in 3.05 seconds = 38.75 MB/sec
gwy:~# hdparm -t /dev/sdb & hdparm -t /dev/sdf & sleep 20
/dev/sdb:
Timing buffered disk reads: 194 MB in 3.02 seconds = 64.31 MB/sec
/dev/sdf:
Timing buffered disk reads: 224 MB in 3.02 seconds = 74.09 MB/sec
gwy:~# hdparm -t /dev/sda & hdparm -t /dev/sdb & hdparm -t /dev/sdc &
hdparm -t /dev/sdd & hdparm -t /dev/sde & hdparm -t /dev/sdf & sleep 20
/dev/sda:
Timing buffered disk reads: 200 MB in 3.03 seconds = 66.00 MB/sec
/dev/sdf:
Timing buffered disk reads: 220 MB in 3.05 seconds = 72.11 MB/sec
/dev/sde:
Timing buffered disk reads: 58 MB in 3.03 seconds = 19.12 MB/sec
/dev/sdd:
Timing buffered disk reads: 64 MB in 3.04 seconds = 21.06 MB/sec
/dev/sdb:
Timing buffered disk reads: 70 MB in 3.03 seconds = 23.10 MB/sec
/dev/sdc:
Timing buffered disk reads: 56 MB in 3.01 seconds = 18.59 MB/sec
gwy:~#
For comparsion 1TB Hitachi behind 3726 PMP (again MS4UM) with sata_sil
patch I sent last week (no NCQ, 1.5Gbps link between 3512 and PMP, and
3.0Gbps link between PMP and drive... why is it faster?):
petr-dev3:~# hdparm -t /dev/sdd
/dev/sdd:
Timing buffered disk reads: 248 MB in 3.01 seconds = 82.48 MB/sec
petr-dev3:~#
Petr
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