On Thu, 20 Apr 2006, Mikael Carneholm wrote:
> We're going to get one for evaluation next week (equipped with dual
> 2Gbit HBA:s and 2x14 disks, iirc). Anyone with experience from them,
> performance wise?
We (Seatbooker) use one. It works well enough. Here's a sample bonnie
output:
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
16384 41464 30.6 41393 10.0 16287 3.7 92433 83.2 119608 18.3 674.0 0.8
which is hardly bad (on a four 15kRPM disk RAID 10 with 2Gbps FC).
Sequential scans on a table produce about 40MB/s of IO with the
'disk' something like 60-70% busy according to FreeBSD's systat.
Here's diskinfo -cvt output on a not quite idle system:
/dev/da1
512 # sectorsize
59054899200 # mediasize in bytes (55G)
115341600 # mediasize in sectors
7179 # Cylinders according to firmware.
255 # Heads according to firmware.
63 # Sectors according to firmware.
I/O command overhead:
time to read 10MB block 0.279395 sec = 0.014 msec/sector
time to read 20480 sectors 11.864934 sec = 0.579 msec/sector
calculated command overhead = 0.566 msec/sector
Seek times:
Full stroke: 250 iter in 0.836808 sec = 3.347 msec
Half stroke: 250 iter in 0.861196 sec = 3.445 msec
Quarter stroke: 500 iter in 1.415700 sec = 2.831 msec
Short forward: 400 iter in 0.586330 sec = 1.466 msec
Short backward: 400 iter in 1.365257 sec = 3.413 msec
Seq outer: 2048 iter in 1.184569 sec = 0.578 msec
Seq inner: 2048 iter in 1.184158 sec = 0.578 msec
Transfer rates:
outside: 102400 kbytes in 1.367903 sec = 74859 kbytes/sec
middle: 102400 kbytes in 1.472451 sec = 69544 kbytes/sec
inside: 102400 kbytes in 1.521503 sec = 67302 kbytes/sec
It (or any FC SAN, for that matter) isn't an especially cheap way to get
storage. You don't get much option if you have an HP blade enclosure,
though.
HP's support was poor. Their Indian call-centre seems not to know much
about them and spectacularly failed to tell us if and how we could connect
this (with the 2/3-port FC hub option) to two of our blade servers, one of
which was one of the 'half-height' ones which require an arbitrated loop.
We ended up buying a FC switch.
