Re: File system compression, not at the block layer

From: Richard B. Johnson
Date: Fri Apr 23 2004 - 15:36:15 EST

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.

There is no redundancy in such an array, just brute-force
speed. One can add additional bits and CRC correction which
would allow the failure (or removal) of one drive at a time.

Dick Johnson
Penguin : Linux version 2.4.26 on an i686 machine (5557.45 BogoMips).
Note 96.31% of all statistics are fiction.

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