Re: [Networker] Staging from a partition or of the folder

Hi Terry.

I agree if you have a RAID-5 optimized hardware platform (Like the EMC).  If
you don't, then RAID-5 will slow your backups down to speeds well below
modern tape drives. I would suggest that if anyone wants to use RAID-5, they
set it up, and try a backup. If the speed is slow, then they should change
to RAID-10 and compare the speed.
I am running 4 hard drives RAID-0, and my backup speed hits 12-13 MB/s on
these drives (on a 10MBPS SCSI bus. Hm, I wonder.....)
When I send data to my RAID-5 hardware array on this server, I only get
3-4MB/s.

Calvin Thomas
UNIX System Administrator
NACA Logistics


-----Original Message-----
From: Terry Lemons [mailto:lemons_terry AT EMC DOT COM]
Sent: Friday, February 21, 2003 5:19 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: Re: [Networker] Staging from a partition or of the folder -
File device?


Hi Wes

Yours are exactly my reasons for using RAID-5 instead of the other choices.
EMC, for instance, has worked very hard to optimize its RAID-5
implementation.  I believe that RAID-5, coupled with ATA disks, is a
compelling backup-to-disk platform.

tl

-----Original Message-----
From: Wes Ono [mailto:wono AT legato DOT com]
Sent: Thursday, February 20, 2003 4:25 PM
To: 'Legato NetWorker discussion'; 'lemons_terry AT EMC DOT COM'
Subject: RE: [Networker] Staging from a partition or of the folder - File
device?



Terry,

I beg to differ on your RAID recommendation.

I would recommend AGAINST RAID-5 for a file-type device.  Each write to a
RAID-5 set results in a write-read-write sequence because of the need to
recalculate and rewrite the parity strip.  This will negatively impact your
performance.

RAID-0 (striping) gives good performance, but had no redundancy in case of
disk failure.  RAID 1+0 (striping across mirror sets) gives good performance
and protection against disk failure, but tends to be expensive, as you need
2*n disks.

Wes

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Re: [Networker] Staging from a partition or of the folder - File device?
