Re: some IDE trays are bad (was Re: SW-RAID 1 and kernel 2.4.18)

On Tue, 2002-12-03 at 08:01, Louis-David Mitterrand wrote:

On Tue, Nov 26, 2002 at 02:56:41PM +0100, SCHEP. - Schepke, Arnt wrote:

quoted

The system seems to work correctly. But i get some errors. In the file
messages i found: 

linux kernel: hdc: dma_intr: status=0x51 { DriveReady SeekComplete Error } 
linux kernel: hdc: dma_intr: error=0x84 { DriveStatusError BadCRC }

I've just had the same problem. My setup: 4 Maxtor 160G connected to a
Promise 133TX2 card, one of them was in an Icy Dock removable rack, the
three remaining were directly connected to the IDE cable. 

The tray-connected disk would always give us the BadCRC error upon
resynching with the raid5 array. That kind of error is typical of bad
cabling.

It seems the additionnal connectors and cable-length in these IDE trays
is too much to bear for picky/sensitive ATA133 drives. In any case the
BadCRC disappeared the moment the drive was directly connected the IDE
ribbon.

It's probably far more the quality of the connectors and such than the
length of the cables.  

hdparm -t /dev/md1 gives me over 100MB/s on IDE raid5. Incredible! Over
twice what a top-of-the-line 15k scsi drive gives me.

Are you saying that a RAID 5 array gives you better performance than a
single disk?  Make sense to me.  I'd be far more interested in a real
benchmark, rather than hdparm.  Across given runs on a single disk, I've
found it to be reasonably reliable, but from one disk to another, not
necessarily.  
	Greg

-- 
Gregory Leblanc [off-list ref]