On Wed, Mar 13, 2013 at 6:37 PM, SilverTip257 wrote: > On Tue, Mar 12, 2013 at 10:10 PM, Keith Keller wrote: > >> On 2013-03-12, SilverTip257 <silvertip257 at gmail.com> wrote: >> > >> > I've not had any MegaRAID controllers fail, so I can only say they've >> been >> > reliable thus far! >> >> I think that this is not a helpful comment for the OP. He wants to >> know, in the event the controller does fail, can he replace it with a >> similar-but-possibly-not-identical controller and have it recognize the >> > > I've had no problem with various versions of Dell MegaRAID/PERC5i > controllers. > You can swap drives from a PERC5i into a PERC6i for example and things are > peachy. But it is not possible to swap drives from a PERC6i into a PERC5i > controller. > No plans to go with Dell hardware but it is great to note that newer models (Dell OEM Megaraid) recognize arrays created with older models. I don't expect an older model to recognize an array created by a newer model. > Avoid SAS6/iR controllers ... they are low-end controllers that only > support hardware RAID0 and RAID1. My configuration will be RAID 5 or 6, depending on how the option the client is willing to pay. > > Ultimately hardware RAID controllers can be a big pain -- just like > anything else it's a good business practice to have spares! > > >> original RAID containers. Just because you have not seen any failures >> so far does not mean the OP never will. >> >> > You start by failing/removing the drive via mdadm. Then hot remove the >> > disk from the subsystem (ex: SCSI [0]) and finally physically remove it. >> > Then work in the opposite direction ... hot add (SCSI [1]), clone the >> > partition layout from one drive to the new with sfdisk, and finally add >> the >> > new disk/partitions to your softraid array with mdadm. >> > >> > You must hot remove the disk from the SCSI subsystem or the block device >> > (ex: /dev/sdc) name is occupied and unavailable for the new disk you put >> in >> > the system. I've used the above procedure many times to repair softraid >> > arrays while keeping systems online. >> >> This is basically the same procedure for replacing a failed drive in a >> hardware RAID array, except that there is no need to worry about drive >> > > I'll argue that the software RAID process is slightly more complex. And it > is crucial that one remember to hot-remove the disk ... after all one > could panic their box by just yanking the drive. > Yes, this could happen inspite of well documented procedures. For this reason, hardware RAID has been a consideration. However, I have come to realize that it has it's own pros and cons as mentioned in this thread. -- Arun Khan