PowerEdge MegaRaid Linux large files

Spangler, Jason jspangler at origin.ea.com
Wed Aug 29 11:17:01 CDT 2001

I am experiencing the same problem on PowerEdge 6350 running RedHat 7.1 with
kernel 2.4.3-12smp and a PERC2 controller (using the megaraid module)
configured for RAID 5.  The copy of a 2GB file hangs the filesystem until it
finishes, which is a bad thing in my particular situation.

Are any fixes available or workarounds known?  RAID 0 isn't an option for


-----Original Message-----
Date: Tue, 28 Aug 2001 11:16:05 -0700 (PDT)
From: Ron Stanonik <stanonik at Cogsci.ucsd.edu>
To: <linux-poweredge at dell.com>
Subject: PowerEdge MegaRaid Linux large files


We bought a PowerEdge 6300 (year or two ago) with 1GB RAM,
six 18GB disks, PERC2/SC (megaraid), and RedHat (6.X at the
time, 7.1 now).

The six disks were configured as one raid 5.

If anyone writes a large file, any other writes hang until the
large file finishes.  Since almost any activity creates files
(email, /tmp, utmp, etc), all activity hangs until the large
file finishes.  Of course the large file must be really large
(>100GB) for the hang to be noticeable, but for us this happens
often enough to be a problem.

We've flashed the latest megaraid BIOS (3.13) and are running
the (almost) latest megaraid driver (kernel 2.4.8, driver 1.17).

If we configure the six disks as one raid 0, then the problem doesn't
occur.  Bummer, we'd really like the protection of raid 5.

We keep hoping that the next BIOS update or kernel version or driver
version will fix it, but not yet.

Wondering if you've encountered this, have any hints, etc.


Ron Stanonik
stanonik at cogsci.ucsd.edu

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