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Duh moments

September 26th, 2010 (02:29 pm)

My desktop at home has four hard drives: one for a boot drive and three for a RAID array. Last week, the boot drive and one of the RAID drives failed. (Root cause: my UPS has failed; it's now an IPS.) So, long involved process: get two new drives, reinstall the OS on one of them, get the RAID array to rebuild drive 3 from the redundant information on drives 1 and 2.

In the midst of all this, I had two "oh, duh" moments:

  • My computer case is really nice to work in. Among other things, the drives are in removable cages, so I can take out the cage, screw a drive into it, and put the cage back. I suddenly realized why: I bought this computer from PCs For Everyone. (The motherboard, the drives, and the power supply have been replaced a couple of times, but it's still the same axe.) PCs For Everyone offers free lifetime support. Sensible cases let them keep those costs down a bit. Duh.
  • The current incarnation of this computer is about 2.5 years old. So it's got a fairly fast quad-core CPU, and 4GB of RAM. But it's always seemed a little slow, and I've sometimes wondered if it's because /home is a software RAID array. I've been assured that, no, Linux software RAID is pretty fast, so it was a mystery...until I went to disconnect the RAID drives. Two of them are IDE, which means the whole array is limited to IDE speeds; but that shouldn't be that bad...except they're on the same IDE cable. (The motherboard only has one IDE channel.) So every write to the array translates to three writes to drives, two of which are contending for bandwidth. So the array is limited to half of IDE speed. Duh.


Posted by: dsrtao (dsrtao)
Posted at: September 26th, 2010 08:33 pm (UTC)

How do you do backups?

Posted by: Who, me? (metageek)
Posted at: September 27th, 2010 02:22 pm (UTC)

Ah. You have noticed the missing element: I don't back it up. I used to back up to DVDs every so often, but these days it would take, I don't know, maybe 50 DVDs. Even if I got a Blu-Ray burner, it'd be about 16 discs.

I should probably get a file server and rsync to it regularly.

Posted by: dsrtao (dsrtao)
Posted at: September 27th, 2010 02:32 pm (UTC)

My suggestion: get two external (USB or eSATA) disks. Use rsnapshot to back up to one. Every week or two, unplug one and replace it with the other.

Posted by: Who, me? (metageek)
Posted at: September 27th, 2010 03:22 pm (UTC)

Hmm. That would probably work.

The advantage of a NAS is that it could live in the house (the desktop is in my lab above the garage), giving some more redundancy. (The house's outer shell is steel and concrete, so fire in the house is unlikely to reach the detached garage, or vice versa.) Meanwhile, I could get a different NAS in the lab, for backing up cvirtue's Mac. We're currently backing that up with an attached USB drive and Time Machine; again, distance would be nice.

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