Slashdot Mirror
Why RAID 5 Stops Working In 2009
Lally Singh recommends a ZDNet piece predicting the imminent demise of RAID 5, noting that increasing storage and non-decreasing probability of disk failure will collide in a year or so. This reader adds, "Apparently, RAID 6 isn't far behind. I'll keep the ZFS plug short. Go ZFS. There, that was it." "Disk drive capacities double every 18-24 months. We have 1 TB drives now, and in 2009 we'll have 2 TB drives. With a 7-drive RAID 5 disk failure, you'll have 6 remaining 2 TB drives. As the RAID controller is busily reading through those 6 disks to reconstruct the data from the failed drive, it is almost certain it will see an [unrecoverable read error]. So the read fails ... The message 'we can't read this RAID volume' travels up the chain of command until an error message is presented on the screen. 12 TB of your carefully protected — you thought! — data is gone. Oh, you didn't back it up to tape? Bummer!"
Lacking in file system utilities (yes, fsck IS necessary even on healthy filesystems, especially on desktops and portables)
So, why is fsck needed? If you'd actually investigated ZFS, you'd know its built to never need such an archaic utility. Either it works or it doesn't, so if it does, then no external checks are needed.
Insightful? lol
A poorly designed multi-disk storage system can easily be worse than a single disk.
Certainly. Though I can't speak for RAID-5 from personal experience, never having used it. I've always thought of that as so complicated, I find it difficult to trust, especially since there is no parity checking.