The Logic Off Topic list

--- In logic-ot@yahoogroups.com, Peter Ostry <po@...> wrote:
>

> Crash course:
>
> No RAID
> One or more drives, all of them independent. That is what you have
> now. Easy to manage, fast, no security. If one single drive gets
> involved for several operations like supporting the operating system
> and recording audio it becomes slower. If the drive fails the data
> might be lost.
>
> RAID 0
> Data gets written to and read from all drives simultaneously. It is
> the fastest type of RAID and has no redundancy which means no
> security. If one drive fails all data of the whole RAID is lost. Good
> for streaming data like video but in my opinion not necessary for
> recording or playing back audio.
>
> RAID 1
> That is mirroring. Two drives are involved which bear almost the same
> data. Data gets written to and read from both drives but not
> necessarily simultaneously. Reading can be faster than with one drive
> if the system is clever enough to use the data from that disk which
> can deliver them faster. Writing might be slower than with one single
> disk. You get a lot of security because if one drive fails you should
> be able to work with the other one alone until you replaced the
> broken drive. I think the reduced writing speed does not really
> affect recording capability. Mirroring is certainly an option for
> people who do not always have a solid backup system or want a short
> interruption time in case of a hardware failure.
>
> RAID 3
> It stripes the data in the same way that RAID 0 does but additionally
> writes parity data to a dedicated parity drive. In case one disk
> failes the controller can restore the data based on the parity
> information to a replacement drive. RAID 3 is designed to employ
> every disk on every input/output operation. Unlike RAID 0, RAID 3 is
> a redundant system which can withstand the failure of one drive and
> has little diminution in performance if one disk fails.
>
> RAID 5
> That one takes a different approach towards striping and parity
> storage to better handle applications that barrage the system with
> many, small input/output operations. Unless RAID 0 and 3 it is
> designed o engage all drives  in the array at the same time on
> different reads and writes. In/Out per second is higher than I/O of
> RAID 0 and 3. Performance is remarkable slower if one disk fails.
>
> Now, what does all that mean to you? Relax and see it practical ...
>
> No RAID at all but a good backup system is good. You can have one
> system disk which bears also your applications, One disk for sample
> libraries and ond disk for audio (and recording of course). Flexible
> and cheap and a modern computer can handle that.
>
> If you want more security, the question is - what for? For the system
> or for your audio data? They should never be on the same disk so you
> have to mirror one or both of them.
>
> If you want speed, speed, speed, you might go for RAID 0. But I don't
> see an advantage for audio. Although the description of RAID 3 sounds
> promising I have never seen a RAID 3 outperforming a RAID 0. That
> might have been been the kind of data but however, RAID 3 is rarely
> used and people who depend on data aren't that stupid.
>
> If you want a fast and reliable redundant system for your audio data
> and if mirroring is not enough for you you should go for RAID 5 which
> is a widely used standard. You need at least three disks for that.
> And because of the parity you lose 25% of the capacity or one drive,
> whichever occures first. In other words: with a minimal 3-disk system
> you get only the capacity of 2 disks. The relation becomes better
> with each drive you add.
>
> Important:
> There are software RAID's and hardware controllers. If you want to be
> really secure do not rely on a software RAID although some of them
> are quite good (the SUN solution for example). I do not know Apples
> built-in software RAID. However, a software RAID draws some
> performance from your computer because it cannot work independently.
> But it is cheap.
>
> I do not know much about RAID 7 which Otto mentioned in his mail but
> be aware that most "RAID people", in this case the people who want to
> sell you a system, speak about SCSI. Our Macs don't have that built
> since a while. SCSI drives are fast, small and expensive.
>
> There are other RAID levels for bigger systems (mirrored RAID 0 for
> example) but I think they are not in out focus here.
>
>
> Hope that helps,
> Peter Ostry


Peter, thanks for all that information it defintitely gives me some ideas. The main reason I
started thinking about this is right now I have 2 MAxtor 250 Gb HD's one cam with the
computer , the other I installed, the one I installed has my iTunes Lib, My 70+ Gbs Of
loops , and scratch disksa for Bias Pro Xt,  and I usually record to it  in live and Logic pro.
Even though I have evberything Backed up on a crap load of DVDs I dont really have a solid
Back up system. A couple weeks ago I started getting A message in disk utility
program ,"Volume Header Needs minor reapir", Well easy enough to fix with reapiar disk
but it made me start wondering ,Is my disk going bad ? So I started think it would be nice
all the way around to have a set up that mirrored the system disk then have a raid set up
fpr my music. One thing that is streange is I changed the nam e of my hd I kept all my
audio stuff on and the problem stopped . the name before was , Audio_HD , Now it is
Audio HD I took out that underscore thinking my be the disk doesnt like have that in it.
Seems silly but that was  the only thing i did different after installing the HD. ANyWay....
Maybe I should use the maxtor in it now to do mirroring for a regular back up , then set
up a raid conf with that Jive 5 and a pci controller that has at least three connections. that
way I could have to seperate raid configurations as far as the one for the two hds for the
system and the other three for recording and library storage.