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20040730: BOUNCE address@hidden: Non-member submission from [Robert Mullenax <address@hidden>]

>From: address@hidden
>Organization: UCAR/Unidata
>Keywords: 200407302213.i6UMDRLW023442

Hi Robert,

Your email to the ldm-users email list regarding software RAID bounced
since the email address you sent the inquiry from:

address@hidden

was not subscribed to the list.  I just approved your subscriptions
to the gembud, ldm-users, mcidas-x, pc-os, and nws-changes lists,
so you could resend your inquiry if you like.

Besides that, I have done a lot of investigation into use of software
RAID under Linux on machines running the LDM.  The last system I worked
on not at the UPC was Gerry Creager's dual Xeon 2.4 Ghz machine that
uses two HighPoint raid controllers (each has 4 IDE channels) and
8 Maxtor 250 GB (7200 RPM 2 MB cache) disks.  After Gerry spent quite
a bit of time trying to get hardware RAID to work correctly (i.e., the
machine not crash), he came over to my way of thinking and tried
software RAID.  He played with several file systems on the RAID (ext3,
jfs come to mind) before settling on ext2 even though it is not a
journaling file system.  He set the block size at 4 KB which I thought
was too small, but the performance of the RAID has made me think
otherwise.

Gerry was also using his machine as an NFS server for awhile, but
I don't know if he is doing that anymore.

If you want to contact Gerry directly, his email address is:

Gerry Creager n5jxs <address@hidden>

Cheers,

Tom

>From address@hidden Fri Jul 30 16:13:26 2004
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>Message-ID: <address@hidden>
>From: Robert Mullenax <address@hidden>
>To: "'address@hidden'" <address@hidden>
>Subject: LDM and SW RAID
>Date: Fri, 30 Jul 2004 17:06:21 -0500
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>
>Could someone that is using software RAID on an LDM box that acts
>as an NFS server e-mail offline?   I have some performance questions.
>Basically I am seeing very slow reads from a 5 disk stripe (16K)
>on SW RAID 0 as compared to a single disk. 
>
>
>Thanks,
>Robert Mullenax
>
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>From address@hidden  Sun Aug  1 10:51:08 2004

Thanks.  Yes, ImpactWeather is now a subsidiary of Universal
Weather..and I forgot that my e-mail changed.  Thanks for making the
changes.

Gerry did contact me.  I am using Solaris x86 9.  Solaris has a minimum
of 8kb stripe width.  Once I lowered the stripe width to that, it seems
to work fine.  Gerry also mentioned the possibility of the bus being
overloaded (5 disks on one controller (U320 SCSI)).   I just have 3
disks in the stripe now...later I will make it 5 disks again with the
8kb stripes and test again.

Sun stil doesn't support any modern HW RAID controllers on Solaris 9
x86..and I am starting to think they won't.  They have show no interest
in making that a priority.  They would rather you buy their external
storage that has RAID on the array.

However, SOlaris 9 x86 has made a lot performance increases and 10 is
even better (beta).  The previous file system speed increase you saw
wit Linux is gone.   UFS+logging is very fast on Solaris now.

Also, and you might pass this on to Steve, Sun has officially released
their Studio 9 compilers which include a FORTRAN for Solaris x86.

I have been using the beta version of these and have seen 30-60%
performance increases over Linux and gcc/g77.

Thank again,
Robert