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It's either that or because you consistently spelled it round-robinn.
by revelation 9y ago
It's either that or because you consistently spelled it round-robinn.
- rkeene2 9y agoThere was discussion about the spelling of "robbin" versus "robin", but that was easily corrected and a new patch submitted. It was definitely the request from the Linux RAID maintainer Neil Brown to provide benchmarks that stopped me from pursuing it further. I created the patch when someonein the Linux IRC channel was reporting this imbalance on their SSDs, so I had no access to hardware SSD hardware to test it on. This was a long time ago.
- rasz 9y agoCounter to common intuition SSD reads arent completely non destructive (they deplete stored charge) and rolling over READ DISTURB counter triggers wear leveling on affected Block. Micron listed 100K READ cycles per block for MLC, 1Mil for SLC, probably 1K for TLC. Thus balancing reads is good for SSD endurance.
- CodeWriter23 9y ago> Thus balancing reads is good for SSD endurance Ergo, non-balanced reading is better for endurance of the array, as it reduces the probability of contemporaneous multi-disk failure. Like disk 2 failing under the read load encountered during a rebuild.
- wtallis 9y agoIn theory, this is true. But the effect of reads on SSD endurance is orders of magnitude smaller than the effect of writes. The reads required for a rebuild aren't going to trigger an endurance-related failure unless the drive was already within one full drive write of failing.
- CodeWriter23 9y agoGood thing you don’t need to write to the remaining drive in a mirror rebuild.
- wtallis 9y agoNot directly, but you will cause some writing to happen internally to the drive if a read disturb is encountered. When the SSD has trouble reading back data due to a read disturb or similar data degradation, it'll recover it using the error correcting codes and then write a fresh copy.