Re: File system compression, not at the block layer

["Måns Rullgård" <mru@kth.se>]

"Richard B. Johnson" <root@chaos.analogic.com> writes:

> On Fri, 23 Apr 2004, Joel Jaeggli wrote:
>
>> On Fri, 23 Apr 2004, Paul Jackson wrote:
>>
>> > > SO... in addition to the brilliance of AS, is there anything else that
>> > > can be done (using compression or something else) which could aid in
>> > > reducing seek time?
>> >
>> > Buy more disks and only use a small portion of each for all but the
>> > most infrequently accessed data.
>>
>> faster drives. The biggest disks at this point are far slower that the
>> fastest... the average read service time on a maxtor atlas 15k is like
>> 5.7ms on 250GB western digital sata, 14.1ms, so that more than twice as
>> many reads can be executed on the fastest disks you can buy now... of
>> course then you pay for it in cost, heat, density, and controller costs.
>> everthing is a tradeoff though.
>>
>
> If you want to have fast disks, then you should do what I
> suggested to Digital 20 years ago when they had ST-506
> interfaces and SCSI was available only from third-parties.
> It was called "striping" (I'm serious!). Not the so-called
> RAID crap that took the original idea and destroyed it.
> If you have 32-bits, you design an interface board for 32
> disks. The interface board strips each bit to the data that
> each disk gets. That makes the whole array 32 times faster
> than a single drive and, of course, 32 times larger.

For best performance, the spindles should be synchronized too.  This
might be tricky with disks not intended for such operation, of course.

-- 
Måns Rullgård
mru@kth.se