HDs for RAID - how identical should they be ?

[dodecahedron]

hi. i hope this is the right section of the forum. if not, please some mod move it.

i bought 2 Seagate Barracuda 7200.7 drives, SATA, 80GB, 7200RPM, 8MB cahce, the newer ones with NCQ.

i was thinking of maybe playing a bit with RAID. now i've heard that for RAID it's best to have identical drives - same brand, model, specs etc.

reading the info off the labels of the 2 drives:
Model: ST380817AS
S/N: 4MR0XXXX (the XXXX are different digits/letters on the 2 drives)
P/N: 9W2932-370
HDA P/N: 100334813
Config: C4R-03
Firmware: 3.42
Date Code: 05277
Site Code: TK
made in Thailand

these 2 drives probably came from the same batch,
how much more identical can you get?

imagine my surprise then when i looked at at the bottom of the drives. not quite so identical as i had thought.

there are 3 chips that i can see.
an oblong chip which is located diagonally.
on drive 1 it's Winbond, on drive 2 it's EtronTech.
i'm guessing this is the memory ???

a large square chip which i suspect is the controller ?
on drive 1 it's agere or a8ere (but in smaller letters below it says Seagate).
on drive 2 it's ST.

a small square chip. on both drives it's TI (but a different serial number, if that's what it is).

well!

OK so my main question is: should i be concerned over this if i want to RAID the drives toghether? (should i go back to the vendor and try replacing on so that both drives have same chips?)
or am i fretting over nothing?

can it be that the manufacturer uses 2 kinds of chips on the same line? i'd have thought that they use a stock from one supplier, and only when that runs out switch to a new stock from (possibly) a new supplier.

if i'm right and the big chip is the controller circuitry, should i be concerned that they are from different manufacturers? will the drives behave/perform differently because of this? or can it be that Seagate has 2 manufacturers producing identical chips for them?
or maybe it doesn't matter at all it's all in the BIOS?

 

[Jiggz]

You're best resort is to set up the RAID and you will find out if the two hdd's are compatible to work in tandem. I sincerely believe they will. Most of the time all you need is the same size and speed, like 7200 RPM and whatever GB size.

 

[imported_rod]

They have the same interface, capacity, speed, cache and both have ncq. If i were you, i'de just throw them in and see if they work. They should do...i mean, you can use HDDs with different interface (i.e. a SATA and an IDE), so i see no reason why these wouldn't work.

Just wondering, which typre of RAID are you going to be trying, redundancy or stripping?

RoD

 

[dodecahedron]

alas, i can't do it just now.
work leave me very little time for tinkering just now (and the next few days).
and my case is cr*p only space for 2 HDs.

i'm a n00b about RAID etc., but i would've thought it shouldn't be a problem. just wanted to ask the gurus around here.

also, i wanted to know if it matters for the RAID array how "identical" the drives are? does it perform better (RAID 0 ?) if the drives are "really identical" and less so if they are similar in specs but not quite the same (different mfgr. for instance but same specs)?

i'm just very curious about this. the 2 drives were obviously produced very "close" (for want of a better word) to each other, as the S/N bears out. so i was really surprised by the differing chips. i was wondering if anyone knew if the different chips are indeed different and if it effect drive performance, behaviour etc.

as for what RAID i'll do, i dunno i've never done RAID thought i'd play with it a bit.
try RAID 0 see if it improves system performance having the OS on a RAID0.
if not maybe do RAID1 for data safety.


thanks for the speedy replies, BTW

 

[lansalot]

They don't have to be identical at all.

Roughly the same size so you don't lose any capacity, and ideally a similar rotation speed would be about the only things worth worrying about.

 

[dodecahedron]

Originally posted by: lansalot
They don't have to be identical at all.

Roughly the same size so you don't lose any capacity, and ideally a similar rotation speed would be about the only things worth worrying about.

really !?
i'm surprised. i was sure i've read that the drives must be identical, RAID works better!

i guess i was wrong!
so i needn't worry about the (apparently) different chipsets.