Presentation: End of RAID5
I often use a thoughtgame when i talk about ZFS: Can we afford to use large harddisks without stronger mechanisms to ensure data validity? The best examples for this problem came from Robin Harris and his Storagemojo.com blog with the article about the reliability of hard disks. I mostly use this example as an anecdote but i transformed it into a <a href=”href=’/uploads/endofraid5.pdf’ target=”_blank”“>draft presentation in the last few evenings</a>:
In my opinion the problem is much worser than described in Robins blog entry: At first you have the time bomb effect of transient read errors described in the presentation. Furthermore better error correction doesn´t solve the problem completly. There are many components between the heads of the harddisks and the CPU. You need checksums for the data from the disk to the CPU. Everything else isn´t a complete solution of storing data on rotating rust while ensuring data validity.