On Mon, 2015-08-17 at 15:32 +0100, Wols Lists wrote: > On 17/08/15 07:28, David C. Rankin wrote: > > On 08/16/2015 07:27 AM, Wols Lists wrote: > >> If you want to add new drives, you can use GPT on them, as I say, if > >> they're large disks, you'll need to use GPT. > >> > >> Sounds like it's a small system, a home system? If you get new drives, > >> make sure they're proper raid drives, like WD Red. I've got Seagate > >> Barracudas, which was a mistake ... > > > > Thank you for your response. It is my office server, but it runs on 2 1T > > drives (Carvair Black) Have had good experiences with them. I toss at > > least 1 barracuda in the trash every 3-4 months. > > Well, my experience with Barracudas has been good - they were my > preferred choice of drive ... > > You saying Black rang alarm bells for me, and I've just looked on my > favourite sales site - it says they are DESKTOP drives! > > YOU NEED TO CHECK THEM OUT WITH SMARTCTL! > > Check if they support ERC etc. The Barracudas I know don't, the Reds > various people have said they do. If the blacks don't support it, then > they'll let you down when you need it. You really don't want to go raid > 5 or 6 with drives that don't support it. I want to go raid 5, which is > why I'm gutted to discover I'll have to replace my Barracudas. imho > they're decent serviceable drives ... Thats not strictly true.... With a non TLER drive if a problem is found the drive might take a long time to fix them internally and the device layer time out might be exceeded. With TLER the drive will always respond within, usually, 7 seconds. I have the following embedded in a bash script: > for x in /sys/block/sd[a-z] ; do echo 360 > $x/device/timeout ; echo -n "$x/device/timeout : " ; cat $x/device/timeout ; done which is "/sys/block/sdX/device/timeout" Now if the drive is TLER it will still respond in 7 seconds (either with data, or an error - no change there), but if I should have any non-TLER drives the device layer will now wait 360 seconds before timing out. (I know, a long time which in most cases would cause frozen I/O, seemingly hung... but hey, who knows the drive might eventually fix its self!) This time out is just as true for non-raid as raid... if a non raid disk takes longer to respond than the time out, you potentially lose the drive... or you've just killed the last I/O commands to it and done a hard reset. (That said, I think its up to the file system to then deal with a timed out disk? should mdadm sit on top of the disk its processing is "disk timed out, kick it".) > > > > I'll stick with MBR and see how it goes. In that case I'll just boot the > > install media and assemble the arrays and see what I end up with. > > > > > Yup. No real point going gpt until you get to 3 and 4TB drives. Once you > can get linux running, it shouldn't care what sort of drives you have, > but if you read the gentoo wiki pages about installing on raid > (disclaimer, I wrote a decent chunk of it), you'll see what a pig it can > be getting as far as loading linux ... > > Cheers, > Wol > -- > 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
