To TLER or not to TLER using onboard Intel raid

Many of the more software based raid styles, like the simple onboard Intel raid, will wait for a long time before freaking out, they can be much more forgiving than a fully hardware based raid Card with onboard processor and onboard ram. Besides you have to Have an error first :-) If my disks were having errors and flaking out the raid to often, in reality I would WANT TO KNOW , even if that means it bails out and I have to reboot , halt the system, and let it complete a hardware task. Then next I am going to be wondering what error it got, and why to took so long to "fix" or hide it.

The noise about the ammount of time set on the TLER is important for many raid systems, so knowlegable raid experts would always say that the time needs to be limited, and "There Is No Other Way". But the same experts will also admit that the more consumer based systems are fully capable of handling the situation of a drive not responding as quick. Because they are more consumer based.

Tidbits from a manufacture: From http://wdc.custhelp.com/app/answers/detail/a_id/1397/p/227,279

When an error is found on a desktop edition hard drive, the drive will enter into a deep recovery cycle to attempt to repair the error, recover the data from the problematic area, and then reallocate a dedicated area to replace the problematic area. This process can take up to 2 minutes depending on the severity of the issue. Most RAID controllers allow a very short amount of time for a hard drive to recover from an error. If a hard drive takes too long to complete this process, the drive will be dropped from the RAID array. Most RAID controllers allow from 7 to 15 seconds for error recovery before dropping a hard drive from an array. Western Digital does not recommend installing desktop edition hard drives in an enterprise environment (on a RAID controller).

It would be Good to read the rest there. Notice how a Cavier "black" does not define a "raid drive" for WD. The (RE) designation does. How many times have you seen users say that "blacks" are the ones to use in a raid system?

Myself I have used consumer disks and more consumer based raid systems for ages, i rarely get errors of ANY sort, and have never had a problem with a consumer drive in a consumerish raid system. I am not running a Web Server, I have a fair idea as to how the hardwares are reacting. I think some of the noise about TLER is overrated. Again, VERY important for some raid systems, or even configurations, but is nothing but noise to me, because all my stuff has not skipped a beat.

If you want less problems you get the right stuff, if you are a cheapskate :-) you can get away with more than any expert would say you could. I also treat my hard drives like they are easily damaged, that means my computer should not even be bumped, while it is spun up.

These answers are not supposed to be "opinion" so the Facts are "proper drives should be used in raid systems" Especially important for high end "full" raid cards. The facts also are that thousands of users are running raid systems with consumer and even green drives with long TLER times in the intel onboard and other lightweight raid controllers . both with a relative ammount of troubles from either.

If the TLER time is greater than the preset timeout period for the controller, the controller could mark the drive as defective, even though the drive is just trying to repair bad sectors. <--- that is the key.

Psycogeek

Posted 2012-03-02T12:15:06.710

Reputation: 8 067

So you are saying that the only negative effect that could come from using TLER is that the system may 'overreact' when things take a long time? – cc0 – 2012-03-02T13:16:33.780

@cc0 Yes like marking the disk as bad, unnessisary rebuilds. the windows system is even capable of crashing or locking up when an i/o doesnt complete. I have seen it occur one time on a promice raid system , went back to check after getting it going again, and there were 13 new bad sectors. . . If we Put in some re-built drive, or one of those re-tested returns from the manufacture, or a drive doing bad seeks and all, and again, I as a user (not web server) would rather it fail, then I test the drive and replace if nessisary. – Psycogeek – 2012-03-02T13:22:13.503

2Part of it is drives are much faster at repairing and relocating bad sectors these days, and ECC is much much better also. so longer timeouts are rare on consumer drives, there was a time when you better use TLER on older consumer drives with raid controllers or else. Seems to be a moot point on modern drives. – Moab – 2012-03-02T16:50:08.883

Welcome to SU. Can you format your answer in a way to doesn't come across so rude. Include specific (ideally technical) reasons as to why you hold this position rather than a life experience. Makes your answer more useful. Thanks. – Matthew Williams – 2014-03-26T15:22:23.393

Please try to focus on providing a factual answer and not just commentary which does not help the OP reach a conclusion. – Eric G – 2014-03-26T15:42:57.093

To TLER or not to TLER using onboard Intel raid

Answers