Trouble acquiring decent hardware.
 
Interested though, is that concurrent operation, i.e. writing at these
speeds and reading at these speeds concurrently?  I'm not familiar with
bonnie++.
 
cheers, Phil

-----Original Message-----
From: veritas-bu-bounces at mailman.eng.auburn.edu
[mailto:veritas-bu-bounces at mailman.eng.auburn.edu] On Behalf Of Tim
Berger
Sent: 27 September 2006 22:37
To: Joe Royer
Cc: veritas-bu at mailman.eng.auburn.edu
Subject: Re: [Veritas-bu] LTO3 and Disk Staging


On 9/25/06, Joe Royer <jroyer at digitalmotorworks.com> wrote: 


As one of the others to ask this question, here are my findings so far:

- Most people aren't keeping their LTO3 happy, some even falling victim
to the marketing crap that "LTO technology isn't harmed by shoeshining."

I have personally seen a 20-25% (per month) drive failure rate in an
environment of constant shoeshining on LTO1.
- Software striping of multiple LUNs may be a good quick fix or stop gap
solution.  Especially if you can aggregate your FC interfaces this way. 
- A few have mentioned that they started using FC disk because SATA was
too slow.


I have no trouble at all keeping LTO3 streaming with SATA R5 or R0 array
staging areas.

Here's a bonnie++ report from such a raid (R0).  197MB/sec writes,
240MB/sec reads.  Fast enough for LTO3 or LTO4, for that matter. 

Version  1.03      ------Sequential Output------ --Sequential Input-
--Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP 
fiik             4G           197803  67 95682  24           240898  23
589.0   1

Oridnary 7200 RPM 300GB disks on a 3ware 9k series raid controller.

Maybe some people are having touble acquiring decent hardware or
configuring their raids. 


7200 RPM SATA drives will never be as fast as 10000 RPM SCSI drives, but
IMHO they're perfect for staging because they're fast enough when
striped and cheap.  Using FC for staging area seems wrong somehow.
They're crazy expensive for use as scratch space. 


-snip-

-- 
-Tim 




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