Well pretty much by definition any writes shorten the drives life, the more writes the shorter it is.
That said, here is some interesting math that I did before I built my first mlc array. For a certain brand of indellix drive I calculated the life span in the following way. Based on the maximum sustained write speed of the drive and the size of the drive (256GB by the way) it would take 9 months to over write the entire drive 10000 times at 100% busy writing. However I knew that my controller would be lucky to keep all the drives at 25% busy (btw turns out that it's really about 12%) so I took the 9 months and multiplied that times 4 coming up with 36 months. Great now we're at 3 years, but we're still doing 100% writes and we know that this isn't going to be the case. In fact we expect the absolute worst case scenario is that we'll be doing less than 25% writes. So again I took the 3 years and multiplied that times 4. This comes out to 12 years to wear out my mlc drives. Just in case I'm calling it 10 years. But you know what? Quite frankly those boxes will be retired in less than 5 years and even then I'll be suprised if it's still my problem to worry about. Of all the issues that might concern me about using mlc drives, them wearing out isn't really one of them. Of course if your useing tiny drives, the math changes. In fact under the above scenario, assuming a 32gb drive went as fast as a 256gb drive (and they don't btw) your 32gb drive would only last about 18 months. Since it's probably only has half the chip count of the larger drive, and thus only using half it's write channels, you probably still have about 3 years of life in the drive running at 25% busy x 25% writes. Just some food for thought. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
