RAID on a budget.

Dakine

n00b
Joined
Aug 3, 2004
Messages
20
Hey guys,
I'm wondering if I buy a computer with only one harddrive if I can easily slap it into a RAID 5 when I Get the cash for the RAID card and second harddrive. So, Use it with one harddrive for a few months, then get the second HD and Card and voila! or no Voila.

And also, is it ok to get a different HD as long as it is the same size?

Thanks!

- chris
 

InorganicMatter

[H]F Junkie
Joined
Oct 19, 2004
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15,464
No. RAID-5 arrays (at least, as I know them) must be "built." This process can take 24-48 hours depending on how many drives you have; it completely zeros out the drives and writes the "RAID" components to the drive.

Also, you'll need at least 3 drives, not 2 to use RAID-5. I suggest at least 4 or more. I also suggest you spending the extra money for a hardware-level caching controller. I've got a SCSI one with 128MB of memory on it, and wouldn't have it any other way.
 

enginurd

Fully [H]
Joined
Jul 17, 2006
Messages
21,825
You need at least 3 drives for a raid5 array, and no, I dont believe they need to be the same brand - just same size (or you lose usage of the extra size... the array will use the lowest common sizing for all drives, per drive).

You can easily slap it into a raid5 array, but all the data will be lost unless you back it up somewhere else.

What will you need the raid5 array for?
 

InorganicMatter

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enginurd said:
What will you need the raid5 array for?
Maybe because it is much faster and safer than a single hard drive? I used dual Raptors for a while, then moved to my hardware-caching SCSI controller, which on paper was technically a "downgrade," but in real life the difference is night and day. I wouldn't have it any other way, the most expensive/elaborate SATA drive on planet earth couldn't keep up with my array.
 

SKy042

[H]ard|Gawd
Joined
Jan 27, 2003
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If you start with 3 drives you can do a raid 5
and if you're using a good Raid 5 card like mine that supports online capacity expansion then you can continue to add drives and making your array larger without losing the whole array and starting over.
 

InorganicMatter

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SKy042 said:
If you start with 3 drives you can do a raid 5
and if you're using a good Raid 5 card like mine that supports online capacity expansion then you can continue to add drives and making your array larger without losing the whole array and starting over.
QFT. Hardware RAID controllers FTW!
 

SKy042

[H]ard|Gawd
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Jan 27, 2003
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1,037
drizzt81 said:
I doubt it is. Apparently this Hpt model is their hardware version. Unlike the 2320 they have plastered "hardware raid offload" all over the page.
Hmm....interesting. I didn't have PCI-X available to me on that machine.
Since it's a stand alone machine that does nothing but act as a network drive I feel pretty confident the Opteron 148 I put in there is plenty to power it if it is a software raid.
Wonder what CPU is under the big heatsink on my 2320 then??
 

unhappy_mage

[H]ard|DCer of the Month - October 2005
Joined
Jun 29, 2004
Messages
11,455
SKy042 said:
Hmm....interesting. I didn't have PCI-X available to me on that machine.
Since it's a stand alone machine that does nothing but act as a network drive I feel pretty confident the Opteron 148 I put in there is plenty to power it if it is a software raid.
Wonder what CPU is under the big heatsink on my 2320 then??
The Opteron 148 should be plenty of overkill - Tweakers.net's review of the 1820a shows ~350MB/s sequential writes... on a single 140.

My guess as to what the chip under the heatsink is would be a pci-e to pci-x bridge. Compare the 2220 to the 2320 and you'll see where I got this idea - on the 2320, many of the traces coming off the heatsunk (?) chip go to the Marvell controller; on the 2220 they go straight to the pci-x bus. So my guess is they took the easy route out and bridged that sucker. The 3220 with the Intel IOP331 uses that as a pci-x bridge, and then has the rest of a 2220 tacked onto that. I haven't seen reviews of the 3220, but I'm interested. This is the same chip as the Areca cards use IIRC; it'd be interesting to see if this is another Promise-like implementation or if it's decent.

 
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