[EMAIL PROTECTED] wrote:
>
> On Tue, 12 Oct 1999, Christopher E. Brown wrote:
>
> > -------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
> > fenris 1024 15716 96.7 45169 70.2 17574 45.8 18524 71.5 47481 38.5 509.5 13.2
> >
> >
> > System is a dual Xeon 500/1mb w/ 512MB main memory. It has 3
> > SCSI busses, one UltraWide (DLT tape), and 2 Ultra2 LVD units (one
> > used, one for expansion). There are 7 seagate 18.2G cheeta drives
> > installed, the last 6 are a 0 spare RAID5 array running left-symmetric
> > parity and a chunk of 128. The filesystem was created as follows.
>
> That's no surprise. I already knew Linux software RAID5 can perform
> extremely well given enough CPU horsepower. The question was, if I want
> hardware RAID5, can I have the benefits[1] it provides and not have crappy
> i/o performance.
>
> [1]
> reliable data storage without having to worry about kernel versions /
> raid driver versions and patches
> automatic rebuilds using hot spares without having to roll my own scripts
> to do so
> ability to boot from a RAID5 (though AFAIK, lilo can boot from software
> mirrored partitions now, no?)
> Not being forced to go SMP just to give software RAID a CPU to play
> on...what if we find our system isn't SMP stable? That may not be
> likely, especially with 2.2.x or 2.4.x, but it was still a serious issue
> with 2.0.x.
Ummm... you could try a RaidZone SmartCan - got a hardware raid5 setup
for about $6000. Performance was pretty close to what I got with
Software Raid - During beta test of the system, I accessed the 5x25GB
drives directly and used the Linux Raid Software to create a Raid 5
array, tested it, then recreated the Raid 5 array using the Raidzone
hardware raid drivers.. The system is a 500Mhz PIII Uniprocessor...
5 x 25GB UDMA - All *master* drives on seperate channels
PCI bus is extended to drive cage.
Hot swappable - haven't tested it thouroughly yet.
Redunant power connections - if you have redundant power supplies.
Some Benchmarks:
Raidzone => Raidzone Smartcan - Hardware Raid5 (/dev/rza)
Oracle-m => Raidzone Smartcan - Software Raid5 (/dev/md0)
-------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
raidzone 1000 6906 89.5 21055 20.6 14558 30.4 7326 89.1 57014 37.6
203.3
2.5
Oracle-m 1000 8254 87.2 18219 16.7 9812 19.5 9707 93.6 34216 21.8
126.4 1.1
Just food for thought...
John
--
John Burton, Ph.D.
Senior Associate GATS, Inc.
[EMAIL PROTECTED] 11864 Canon Blvd - Suite 101
[EMAIL PROTECTED] (personal) Newport News, VA 23606
(757) 873-5920 (voice) (757) 873-5920 (fax)
