Raid + ??

Ok so what is this called:

I have two SATA drives on RAID 0 and I use a 3rd to do backups with xxcopy or Casper XP. I don't like having a mirror disk because if the drives malfunction and copies faulty data then it automatically get mirrored before I have a chance to realize the error. So I think what I have is a RAID 0 + delayed mirror (user choice of when)....so perhaps RAID 0 + D1??

Is there such a thing as delayed mirroring (like 24 hours might be nice)?

Ive never heard of delay mirroring... You just do it manually whenever you want to. All you have is Raid-0.

It's not RAID, it's simply called backing up....in all reality RAID 0 isn't "redundant" so you have no RAID, and you just manualy backup. When I was running RAID 0 I did the same thing, and it works well, but RAID 0 offers no real benefit for me since I don't use massive files. Now I just run a backup at night.

ajrettke said:

It's not RAID, it's simply called backing up....in all reality RAID 0 isn't "redundant" so you have no RAID, and you just manualy backup. When I was running RAID 0 I did the same thing, and it works well, but RAID 0 offers no real benefit for me since I don't use massive files. Now I just run a backup at night.

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So if I use RAID 1, which is called mirroring, I can actually get the same benefits as RAID 0 (ie: on reading both HDs can be read at once, so you get 2x the performance) and you get the benefit of mirroing as well? But on writes you take a hit because the HDs have to write twice?

No that wasn't too clear...RAID was designed so you could use lots of small inexpsive discs to make them appear as bigger ones, all while having data reduncy (if some fail you don't lose everything). Now it's used for almost purely data safety. RAID 0 is zero because it doesn't have any safety.

Raid 1 is simply writing and reading the data to two drives, in theory there should be no performance loss, but in practice there is.

Raid 0 is misleading because :
RAID stands for either (it's changed) "Redundant array of independant discs" or Redundant array of inexpensive discs". The latter is the older term which was around when it was more economical to use 4 discs of small size and making them appear to be one size, than to just buy one big disc. The former is used mainly for data integrity and safety.

Raid 0 in theory writes and reads twice as fast as a single disc, but in practice has slower seek times and anywhere from 1.25-1.75 (just a ballpark figure) increase in throughput.

What your suggesting is simply combining different backup and safety/performance measures. Also since your using two different ways to control them I wouldn't consider it an array. If the onboard controller did this then we could start considering a name for it.
It doesn't really make sense though that you would want to wait to make sure the data is correct...I mean if your working in photoshop just save the file as another name before you edit...and if your really concerned over data, why not just run whatever you want for your HDD setup (solo, RAID 0, RAID 1, 5 or whatever) and then incremental backup every night so you can go back weeks to grab an old file.

ajrettke said:

Raid 1 is simply writing and reading the data to two drives, in theory there should be no performance loss, but in practice there is.

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According to Intel's Accelerated RAID driver info, RAID 1 is twice as fast at reading because two disks have the same info and that info can be read 1/2 from each disk so it is read twice as fast. On writes, there is no penalty to write different drives at the same time.

On the other hand RAID 0.....combines drives so you get a speed performance increase both in reads and writes. The bigger the files read, the more performance you get.

So, is Intel's RAID 1 the only one to show a performance boost in reading? Any one know of a review of it?

I liked delayed mirroring because often I install new programs and then they muck things up or I dont like them and I never find that uninstalling them ever completely removes them...especially since they always leave their trace in the registry. One time, after trying to install an ATI card several times, I discovered that each time the card was install/uninstalled, it left stuff in the registry. In the end I manuall removed over 700 instances of ATI crap in there. After that the install went perfectly! Same thing happened with a USRobotics modem, it also left hundreds of repeat traces in the registry...thank god for regedit. Hence for me, mirror AFTER I know it works, not while I am making mistakes.

I do agree, ordinary data can be backed up nightly so that isn't a problem. Often program errors/changes go unnoticed for weeks until you start using some other program and ooooops it don't work properly anymore. My latest example is an ATI TV card....installed in a top end machine and never has worked....had to dump that stupid thing after finding out that Microsoft had it on its OOPs list...geez it even managed to crash XP repeatedly and that takes some doing! Wonder what it would have done to mirrored RAID system?