> Patrick Hoover wrote: >> Is anyone else having issues with USB interfaced disks to implement >> RAID? Any thoughts on Pros / Cons for doing this? > > Sounds like a very good stress test for MD. > > I often find servers completely hung when a disk fails, this usually > happens in the IDE layer. > If using USB disks circumvents the IDE layer enough, using USB disks > might get rid of these hangs. Would be nice at least. Maybe I'm just > dreaming. > > For end users, USB might remove the need to take special care of > cooling in your cabinet. > OTOH, most USB disk enclosures have horrible thermal properties. > > USB would make it a lot easier to add new disks (beyond your cabinet's > capacity) and to remove old disks when/if they're no longer needed. > Users might run into a bandwidth issue at some point.. After I got rid of a crappy USB hub the catastrophic resets stopped. And after I bought a separate PCI USB card the non-catastrophic resets have almost stopped as well. So now the system works as well as I hoped when I planned it! And no, nothing hangs except the disk access to the device in question when a disk fails. My Seagate disks DO generate too much heat if I stack them on top of each other, which their form factor suggests they would accept. If I put them a bit more spacy though it works perfectly. And there ARE enclosures with separate fans. I have 10 external USB disks now - I got rid of my internal ones which were too old and failing, and I plan on continuing to add on to my external array. My RAID5 + LVM + dm_crypt + XFS setup allows for a very extendable system. And as long as I treat the entire disk set as one device, the bandwidth will not be an issue since I will never demand more bandwidth from the entire array than from a single USB drive anyway. //Martin - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
