Raid Disk

Ok I I will rephrase:
I know enough about RAID arrays to answer basic questions.
I could be of great use to your company though...I make good tea, can clean windows and if needs be I can be used as a VERY effective draught excluder.

Peter

 

For the record

there are only three types of raid, microsofts incarnations are utter bollox...

There is

Raid 0 - no fault tolerance 5 x 200gb disks would give you a massive storage of 1tb, but if one disk goes your shafted.

Raid 1 - disk mirroring 2 X 250gb disks gives you 250gb of storage, but one disk can fail without data loss.


Raid 5 - minimum of three disks required, 3 x 250gb would give you 500gb of storage as you lose a third of the space for the redundancy, 4 diks you lose a quarter, 5 disks you lose a fifth and so on

Raid should be controlled at a hardware level which is invisble to the running operating sytem.

S

 

Nope (on the only 3 types part anyways)...theres plenty more than 3! Especially when you start to consider nested arrays, RAID 50 anyone?

RAID 0 technically technically shouldn't be called RAID either (where does the 'redundant' bit come into striping, where a single disk failure means you will lose all of the data? ).

Back to my own experiences, I run RAID 1 for my music/documents/videos on a home PC with 2x 200GB hard drives. Generally its been fine, ironically since running RAID I've never had a drive in the array fail but I have tested 'rebuilding' the array from either drive by simulating a failure and its worked fine.

The only problem I've had was when the controller card died (Adaptec 1210SA) which corrupted the data on both drives, so I had to start from scratch. The ideal solution for me would be RAID 0 with a spare 200GB drive, and Norton ghost. As Oedipus says, theres still potential for data loss to occur in ways other than drive failures.

 

I'm right

honest mister!!

Any other incarnations are variations on the theme

I also forgot to state rule 1............

Data does not exist unless it is in two places

S

 

Wow issues of philosophy and physics raised in one line - nice.

 

I utterly agree - if we were discussing IT. But I would be happy to take my chances for a domestic music serving solution. The biggest objective/benefit I would be seeking is extensible storage space - I wouldnt even bother configuring a hot spare on a six disk array.

I'd take my chances because I have the CDs/DVDs

It all depends on what hardware you choose, I personally would tend to always choose hardware RAID control, though in this case software based is a consideration because the performance hit on the CPU isnt a problem.

As a good comparison - on of our hosting servers - a 2U IBM X Series 345 - 6 disks SCSI array - 8 fans (8?!) - sounds like a Boing 747 warming its engines up! Very over engineered.

But our recently bought SATA based Dell PowerEdge 1800 is very quiet - and it contains 6 disks in a RAID array. I'd happily have it at home though obviously not in the listening room - its actually quieter than most desktops and at home we'd only configure it with 1 CPU.

In short - you make some good point regards the importance of the broader picture when considering issues of redundancy but I am happy that for the purpose - a Dell PE 1800 with six disks would form a good home entertainments server and also act as a general home data/storage solution (photos, docs, etc.) - if I did consider a NAS solution then this would also be mindful of the additional scope to support other domestic data storage functions beyond just music serving -but obviously the costs go up. Do you see what I mean?

 

ATA drives (sata or pata) typicaly have a CSS spec of 50K (Contact start Stop - or power cycles). So...Lets say you want your home audio server to power down after an hour of no use to save heat, noise, money.

If you do this 5 times a day.....//does maths in head//......you can do this for a considerable number of years before you run into trouble.

BUT!!!! Even though the drives are reliable, I think you would need a very good PSU to match that reliability.

BUT!!!! I personaly would only power down once a day (night time when not in use) as leaving the drives idling can actually help reliability.

Reliability is the key word for RAID systems, and key to reliability is heat. The cooler you keep your drives, the longer they will last - simple as that. Leaving a home server with a conundrum - pitching cooling against unwanted noise. When you can hea your media RAID box situated in a bedroom - from your living room - it simply wont work.

From my perspective you should all build massive RAID boxes with high end fibre channel drives

But when I build mine - it will be a 2 drive system tops. Then a nice 400Gb external SATA drive for weekly backup. Or - hire some server space - say a couple of terrabytes and use you broadband link to backup - let the server provider buy the fibre channel gubbins

 

Thanks for the heads up on powering starting/stoping the drive. Spinning drives up and down in somwhat far in the future at the moment as I've been busy for the last couple of days getting (what should have been) far simpler stuff to work!

 

Hi Oedipus - whatya working on? PM me if you need more specs, design considerations and stuff.