On 14/06/13 16:41, James Harper wrote:
Hi James,
I'm no expert in these things but I wonder if it might not be caused by an electrical/USB problem rather than a filesystem one. So either a controller inside the disk, or in the caddy/enclosure, a cable, or the usb system in your server, or any intervening usb hub. Could be. The cause doesn't necessarily matter to me, I know these things happen, what matters is whether my server stays up when a non-essential filesystem has some errors. I would have thought it does matter. If the problem was USB causing an interupt storm (and that was also my first thought from your description) then no amount of changing the file system is going to help.
I'm not sure how you'd rule this in or out, other than trying to reproduce the fault with a lot of plugging/unplugging, something you might not want to do if that server is of some importance. Maybe you could also try the same disk in a different caddy. I forget the details, but when I had trouble with an interrupt storm on a server's USB, I found a command that allowed me to see the number of interrupts generated so far for the USB device, so I could see how fast that figure was climbing. It was supposedly fixable with a firmware update, but my only use of USB was to occasionally plug in a keyboard, so I just removed USB and used PS2. I wiped the disk (reformatted as xfs) and it appears to be fine so far. I was checking the disks to go into backup rotation (had been used previously at another site that had outgrown them). This disk will be used early next week so if there are any actual problems with the media I should find out then.
So far so good then. It doesn't really tell you much about the cause, but if the problem's gone... I'd be just a bit wary though of a disk that's failed before for unknown reasons. Test your backups now and then, and don't use this for the only copy of anything important. Regards, Andrew McNaughton