pc vs mac, eac vs itunes

Kijanki,

RAID and JBOD (Just a Bunch Of Drives) is somewhat different. First, RAID (except RAID 0, which just mirrors drives) puts different pieces of the data on different drives. JBOD usually functions as multiple drives melded into one. So with RAID data could likely be spread across multiple drives, less typical with JBOD. When reading, this means that each drive can access different parts of that data and the controller pieces it all together, and could theoretically be faster. (There is a penalty, however, when writing.)

Your assertion that reliability is affected by RAID because "one drive fails, you lose both" is incorrect. First, if you only have 2 drives, you use RAID 1, which basically means that each drive is a mirror image of the other, so losing one means you still have an identical functioning copy. With 3+ drives you can use RAID 5, which spreads that data across all drives and also scatters redundant data such that effectively the total of one drive is used to store the redundant information. Now if you lose one drive it is completely reconstructable using the redundant information scattered across the remaining drives.

RAID's purpose (except for RAID level 0, which offers no redundancy) is to preserve data in the event of a drive failure. I repeatedly warn people, though, that it does not protect against other common causes of lost data, such as accidental deletion of files, user screwups, viruses, etc. That's what backups are for!

Michael

Sufentanil

Raid level 0 (stripping mode) can and is often used with two drives to increase performance. My Dell computer at work is set at this mode and I used to have home built computer that had two drives in stripping mode. Striping increases speed both for Read and Write http://www.prepressure.com/library/technology/raid

Your assertion that Raid 0 is not used with 2 drives is incorrect. Here is standard Dell Aurora Desktop configured as default 2x500MB=1TB Raid 0 http://www.dell.com/us/en/home/desktops/alienware-aurora-alx/pd.aspx?refid=alienware-aurora-alx&s=dhs&cs=19&~oid=us~en~29~alienware-aurora-alx-anav-1~~

Another advantage of stripping is space. Putting drives in Mirroring wastes one disk. It becomes backup that can be damaged at any moment by OS or virus. In addition I don't see any need to backup data constantly. If there is any need to backup data constantly on MAC it is better to setup second drive as time machine for the other drive. I don't care much for Raid since I had many programs (like "Go TO") that refused to be installed on Raid drives.

Sufentanil: As my music collection is too large for one 1TB drive I am considering using two such drives and saving copies of those two drives to two external 1TB drives as backup. Is there any reason that this is not feasible? Will playback software be able to automatically search across both drives to search for an item with or without having to tell the software which drive to look at? In other words, what do I gain or lose by having two drives - two partitions as opposed to one large partition?

I use a NAS 1TB LaCie 2Big in Raid 1 (mirror). I set it up wireless. It has been working fine so far with MAC Itunes and an airport. My only issue is our microwave which interferes with wireless comms.

I usee Apple lossless and I can get about 3000 CD's with 1TB of space.

Kijanki,

I think we're basically making the same argument: RAID (0, 1, 5) is OK, but backups are imperative.

Musicnoise, how large exactly is your music collection and how fast do you anticipate it growing? If it's slightly over 1TB, then the least expensive option would be to get 2 1.5 or 2TB external hard drives, one for production use and the other for periodic backups. If it's in excess of 2TB or threatening to go there, then you should probably look at external enclosure that gang together at least two drives and run them in RAID 0 (no redundancy but maximal use of storage space). You will need two of these gangs of drives, because that's how you'll make your backups.

As an example of something you might consider, Try this from OWC.

Can you use two completely separate external HDD's to store your data on? Yes. Most software (including iTunes) should handle this just fine. And you can even create some trickery using symbolic links if you're on a macintosh to make those external drives appear as though they're available elsewhere on the filesystem. (Go to the command prompt and type 'ln -s source_directory target_directory' but this is an advanced exercise that I don't think you'll need to do.) But there are enough relatively inexpensive external enclosures that accommodate 2 drives and automatically provide RAID 0 that I'm not convinced there's a real benefit to having two separate external drives (and then another two for the backups) when you can simply have them in the same box.

Michael