Just be aware that Software RAID has its settings saved in the software of the OS so it can be a right mare to recover from. Thats when i decided to start looking at even the lower end hardware cards...
Regards On Fri, Feb 14, 2014 at 10:32 PM, Jim Stewart <jstew...@paceaudio.com>wrote: > Here is what I will add to this RAID discussion: > > > > 1) The best description of the difference between hardware and > software RAID is "what CPU is doing the RAID". A true hardware RAID > doesn't tax the host system for RAID functions. That said on many > workloads, (like I'd expect most Rivendell ones) there is likely plenty of > spare CPU cycles to do RAID while the CPU is likely just waiting for I/O > anyway. Video Rendering is likely a different story! > > 2) People do get a false sense of security with RAID. As previously > mentioned, it does not protect you from corruption, accidental deletions, > etc. More than that people often don't consider how they are going to > have to deal with an actual RAID system failure. Consider the following: > > a. I've seen I many times, someone has a fancy, high-priced > hardware RAID system on a mission critical system so that they can sleep > nights feeling pretty protected. Suddenly the RAID hardware goes down! > Did they think about having a space RAID box laying around? No! They have > to get a new one flown in at great expense only to be out priced by the > expense of the actual down time! > > b. Okay so you have one of those motherboard BIOS based software > RAID setups (that a lot of people **think** is hardware RAID), in this > case you typically get the worse parts of software and hardware RAID in > this situation. Not only are you still stealing main CPU cycles, but once > again now the motherboard goes down and you have to find another one that > does that system's way of doing RAID! > > c. Now consider Linux software RAID. You can have all the hardware > failures you want and simply boot your Linux + RAID set up on new hardware > and you are up and running again! The only drawback here is your stuck > with running Linux (LOL) to operate your RAID. > > 3) Linux RAID also seem less picky about choice of hard drives as > you can mix and match (although typically not the greatest idea for > performance reasons), and all is fine. Also I don't know about those BIOS > RAID solutions, but if you have hot-swapable drives, you shouldn't have to > shut down your system to replace and rebuild drives. Granted most good > hardware RAID systems give you this too. > > > > I've been subject to another advantage of RAID: I've recently had lots of > trouble with modern hard drives that have "not-quite-defective" sectors. > This has been a real pain for me as the whole system stalls out as the hard > drive struggles to read data in a "not officially bad sector", which it > eventually does, but only after a system slowdown. I wish someone would > write a good disk tester that as real short time-outs so to mark these > marginal areas bad and be done with it! Anyway, with RAID mirroring, it > seems like the system runs just fine (as long as you are reading, not > writing) as any bad spots on one drive are read instead by the other one in > the mirror set. Yea I know, why am I messing with bad drives? The truth > is I can't seem to find any that don't do this these days, I think I've > tried all the (few remaining) hard drive makes/models there are. I've been > told that if I go with some sort of "high-end" drives like SAS interface > ones, that the QC is higher on them and I probably won't have the problem. > It would be too bad if this is what it takes. > > _______________________________________________ > Rivendell-dev mailing list > Rivendell-dev@lists.rivendellaudio.org > http://caspian.paravelsystems.com/mailman/listinfo/rivendell-dev > > -- Nathan Lawson
_______________________________________________ Rivendell-dev mailing list Rivendell-dev@lists.rivendellaudio.org http://caspian.paravelsystems.com/mailman/listinfo/rivendell-dev
