I can offer to you rebuilding that md in a test environment, and giving you access to it, if you're interested.
Can you hook up those failed drives to a different controller? Say, ahci or ata_piix and put them under write load (ext3 w/ barrier=1 and copying lots of files into it should work) and see whether the problem reproduces?
Here are the errors I get, though look at it closer, I am don't appear to be getting the reset, just this error from time to time:
sd 9:0:0:0: [sde] 976773168 512-byte hardware sectors (500108 MB)
sd 9:0:0:0: [sde] Write Protect is off
sd 9:0:0:0: [sde] Mode Sense: 00 3a 00 00
sd 9:0:0:0: [sde] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
ata8.00: exception Emask 0x0 SAct 0x0 SErr 0x280000 action 0x0
ata8.00: BMDMA2 stat 0x687d8009
ata8.00: cmd 25/00:80:a7:00:1d/00:01:1d:00:00/e0 tag 0 cdb 0x0 data 196608 in
res 51/04:8f:98:01:1d/00:00:1d:00:00/f0 Emask 0x1 (device error)
ata8.00: configured for UDMA/100
That's device abort error on read. The drive just can't read sector one of the requested sectors and it's not sata_sil24. It's a bmdma one.
I have 4 identical disks, with all 4 connected to the SIL controller all give some errors, moving 2 of the disks to a promise controller makes the errors go away on the 2 connected to the promise controller. All drives are part of a software raid5 array.
Ah.. okay, sata_sil. Roger, the moving and errors are not very likely to have anything to do with each other. The only possibility is transmission problems but the drive didn't report transport error (ICRC) and it's more likely that the drive was experiencing temporary failures. It's also possible that the drive set ABRT although there was some problem with the transport tho.
If you move the drive back to the sata_sil, do those problems appear again? Anyways, this doesn't really have anything to do with what Hans is seeing.