} -----Original Message----- } From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- } owner@xxxxxxxxxxxxxxx] On Behalf Of Maurice Hilarius } Sent: Wednesday, January 14, 2009 3:03 PM } To: linux-raid@xxxxxxxxxxxxxxx } Subject: Interesting article } } I read this today: } http://blogs.zdnet.com/storage/?p=162 } } Would anyone who knows enough about this care to comment? } } Thanks in advance for any thoughts.. } } } -- } With our best regards, } } //Maurice W. Hilarius Telephone: 01-780-456-9771/ } /Hard Data Ltd. FAX: 01-780-456-9772/ } /11060 - 166 Avenue email:maurice@xxxxxxxxxxxx/ } /Edmonton, AB, Canada/ } / T5X 1Y3/ I have seen RAID5 arrays loose data because of a bad block during a rebuild since the late 1990's. Even on big hardware RAID systems. I now use 3 or 4 way mirrors or RAID6. RAID 5 is too risky for me. Back in the 1990's we mirrored some RAID5 data, but only about 5% of it. The really important stuff. And that has saved the day at least once. Daily read tests are needed, but they don't give any guarantees! I disagree with the statement "So RAID 6 will give you no more protection than RAID 5 does now". Not true at all, RAID5 has always had this problem and can't recover. RAID6 can, even with many bad blocks. As long as you don't have 2 bad blocks on the same block stripe. However, if a RAID6 has a double disk failure and you try to recover, you now have a problem if a block is bad on another disk, and the chances of that are good with really big disks. Guy -- 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
