SATA or SCSI drives - Multiple Read/write speeds.
alvin at Mail.Linux-Consulting.com
Mon Dec 8 18:15:24 EST 2003
hi ya robin/bill
On Mon, 8 Dec 2003, Bill Broadley wrote:
> In my experience there are many baises, religious opinions, and rules
> of thumb that are just extremely BAD basis for making these related
> decisions. Especially since many people's idea about such things change
> relatively slowly compared to the actual hardware.
> My best recommendation is to either find a benchmark that closely resembles
> your application load (Similar mix of read/writes, same level of RAID, same
> size read/writes, same locality) and actually benchmark.
> I'm sure people can produce a particular configuration of SCSI, ATA, and SATA that
> will be best AND worst for a given benchmark.
yupperz ... no problem ... you want theirs to look not as good, and our
version look like its better... yupp ..
definite yupppers one do a benchmark and compare only similar environments
and apps ... otherwise one is comparing christmas shopping to studing
to be a vet ( benchmarks not related to each other )
for which disks ...
- i'd stick with plain ole ide disks
- its cheap
- you can have a whole 2nd system to backup the primary array
for about the same cost as an expensive dual-cpu or scsi-based
for serial ata ...
- dont use its onboard controller for raid ...
- it probably be as good as onboard raid on existing mb...
( ie ... none of um works right
works == hands off booting of any disk
works == data resyncs by itself w/o intervention
but doing the same tests w/ sw raid or hw raid
controller w/ scsi works fine
> So I'd look at bonnie++, postmark, or one of the other opensource benchmarks
> see if any of those can be configured to be similar to your workload. If not
> write a benchmark that is similar to your workload and post it to the list asking
> people to run it on their hardware. The more effort you put into it the
> more responses your likely to get. Posting a table of performance results
> on a website seems to encourage more to participate.
other benchmark tests you can run ....
other tuning you can to to tweek the last instruction out of the system
> There are no easy answers, it depends on many many variables, the type
> of OS, how long the partition has been live (i.e. fragmentation),
> the IDE/SCSI chipset, the drivers, the OS, even the cables can have
> performance effects.
(look for the) picture of partitions/layout ... makes big difference
> The market seems to be going towards SATA, seems like many if not all major
> storage vendors have an entry level SATA product, I've no idea if this
> is just the latest fad or justified from a pure price/performance perspective.
if the disk manufacturers stop making scsi/ide disks .. we wont have
any choice... unless we go to the super fast "compact flash"
and its next generation 100GB "compact flash" in the r/d labs
which is why ibm sold its klunky mechanical disk drives in favor
of its new "solid state disks" ( forgot its official name )
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