Basic RAID question

  • Thread starter Thread starter Jorge E. Ravelo
  • Start date Start date
J

Jorge E. Ravelo

When setting two SATA IDE drives in RAID for fastest performance (RAID 0 ?)
with two mirroring drives, is the total capacity a sum of each drives
capacity, or equal to only half the total?

Pardon my ignorance, as I am a SCSI guy.

Jorge
 
Jorge E. Ravelo said:
When setting two SATA IDE drives in RAID for fastest performance (RAID 0 ?)
with two mirroring drives, is the total capacity a sum of each drives
capacity, or equal to only half the total?

Pardon my ignorance, as I am a SCSI guy.

Jorge
Click to expand...

Raid 0 and mirroring are an oxymoron.

Raid 0 (striping) will give you twice the capacity of the smaller drive.

Raid 1 (mirroring) will give you the capacity of the smaller drive.

Obviously it is standard practice to use identical drives across the
array.

A "SCSI guy" should be more in the nous than anyone else!

Odie
 
A "SCSI guy" should be more in the nous than anyone else!

Odie
--

RetroData
Data Recovery Experts
www.retrodata.co.uk
Click to expand...


Thanks for your response OF!

The reason I am such an ignoramus is that with my Adaptec 2940UW
controller I am not able to mirro/strip anything as it is a non-RAID
controller.
This card, with my original Quantum Atlas 10K drive has served me faithfully
and transparently through many a PC rebuild, possibly four different setups
since purchased! Now it resides in a Pentium 4 ASUS p4800E-Deluxe mobo that
has a SATA Promise RAID controller, and as my supplementary IDE HD (a WD
78mb buffer 80 Gb)( is slower than the Atlas, I thought setting up a RAID
stripping setup with two WD 10 k RAPTORS would speed up the system.

Have a good evening,

Jorge
 
Most modern OS will stripe or mirror your SCSI drives on that 2940UW with no
problem. It isn't quite as fast as a dedicated RAID card, but it can be
done.

--Dan
 
Jorge E. Ravelo said:
Thanks for your response OF!

The reason I am such an ignoramus is that with my Adaptec 2940UW
controller I am not able to mirror/stripe anything as it is a non-RAID controller.
This card, with my original Quantum Atlas 10K drive has served me faithfully
and transparently through many a PC rebuild, possibly four different setups
since purchased! Now it resides in a Pentium 4 ASUS p4800E-Deluxe mobo that
has a SATA Promise RAID controller,
and as my supplementary IDE HD (a WD 8MB buffer 80 GB)
Click to expand...
is slower than the Atlas,
Click to expand...

And an original Atlas 10K is already quite slow itself, compared to that 80GB WD.
I thought setting up a RAID stripping setup with two WD 10k RAPTORS
would speed up the system.
Click to expand...

If your slow Atlas beats an 80GB WD then you must be doing lots and lots
of small record IO, almost entirely. Even one Raptor should beat the Atlas.

What you need is better access time, not better STR.
 
dg said:
Most modern OS will stripe or mirror your SCSI drives on that 2940UW with no
problem. It isn't quite as fast as a dedicated RAID card, but it can be
done.
Click to expand...

I believe (this is certainly the case with Microsoft products; not sure
about Linux, etc.) you can only stripe a second partition; one cannot in
any way have the OS itself run on a RAID array.

I have not done it myself, but I have also heard the results are quite
efficient, speed-wise.

Odie
 
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