This sounds an interesting proposition for RAID 1 setups that I am using. In a couple of cases I have seen unresponsive drives retrying on a bad block seemingly to lock up my system, or at least slow response significantly. In my case I am using Seagate and Hitachi drives. A look at Wikipedia indicates that on Hitachi there is something called "Command Completion Time Limit" and on Seagate "Error Recovery Control". Please can anyone tell me how I would go about setting timeout values on these types of drive. Are there utility programs to do this or a Linux command. Thanks Simon. -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Maurice Hilarius Sent: 09 September 2009 02:34 To: Mario 'BitKoenig' Holbe Cc: linux-raid@xxxxxxxxxxxxxxx; iusty@xxxxxxxxx Subject: Re: mdadm and TLER (Time Limited Error Recovery) Iustin Pop wrote: > .. >> Anyways, clarification... >> The only reason for TLER (Time Limited Error Recovery) is to behave >> "friendly" toward RAID controllers that timeout disks. >> In fact, md does not timeout disks as many Hardware RAID controllers do. >> So, from md's point of view, TLER is useless, i.e. it has no benefit. >> > > I'm sorry but I disagree here. *Especially* because md is used over > normal SATA controllers most of the time, TLER is beneficial because the > drive doesn't go catatonic for minutes at a time trying to recover a bad > sector, which would (because md doesn't timeout disks) cause md to hung > up the whole device. TLER will allow md to see the error quickly and > attempt to rewrite (read) or retry/fail the disk (write) for a bad the > sector. > > Just my understanding of the md stack. > > regards, > iustin > > I agree. Before WD implemented this we would see cases quite often where a perfectly good drive would get "kicked out" of a RAID as frequently or even more often, than on a hardware RAID. TLER management seems to have eliminated most of these cases. -- Regards, Maurice -- 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 -- 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
