kern/92518: Intense disk activity (large FS newfs and/or many small files copy): DMA completion error with RocketRAID-1820A and FastTRAK-S150

[phillip at it.jcu.edu.au]

The following reply was made to PR kern/92518; it has been noted by GNATS.

From: phillip at it.jcu.edu.au
To: bug-followup at freebsd.org
Cc: phillip at it.jcu.edu.au
Subject: Re: kern/92518: Intense disk activity (large FS newfs and/or many small files copy): DMA completion error with RocketRAID-1820A and FastTRAK-S150
Date: Thu, 16 Feb 2006 22:37:43 +1000

 The following work-around for this bug has proved successful:
 
 1) use the RocketRAID for a RAID-1 arrays constructed on pairs of disks.
 Assuming same sized disks, you'll end up with same sized RAID-1 arrays.
 
 2) instead of using the RocketRAID drivers for striping to produce a
 RAID-10 array, use a GEOM stripe across the RAID-1 arrays.
 
 This allows newfs of 240GB file systems with no problems, and test copies
 of large numbers of small files (such as are in /usr/ports and /usr/src)
 also works fine.
 
 In addition, the RocketRAID driver can still manage on-line spare disks in
 the underlying RAID-1 arrays.
 
 The speculation that led to this work-around was that perhaps the EDMA time
 outs are being caused by events being confused between the RocketRAID
 software drivers associated with RAID-1 and RAID-0.  Having RocketRAID
 handle RAID-1 and GEOM handle higher levels gets around this.  However, I
 have not tested this speculation.
 
 The RocketRAID RAID-1 + GEOM stripe arrays have been in normal use for
 about almost week.  It looks good.
 
 Note system update: the system has gone from 6.0-STABLE to 6.1-PRERELEASE
 during which the RocketRAID driver has not changed.