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Best Redundant Storage for Home Use?
Brad Mace asks: "Despite my hard drive's dedicated service, I'm aware that it will someday fail. I'm not really interested in burning 100 CD-Rs to backup my hard drive, so I've been looking at RAID solutions. Obviously I don't need the best or the fastest stuff out there. What would be a reasonable setup for personal use? Have people had better experiences with internal raid arrays, external raid towers, or networked storage such as Snap servers? I'm primarily interested in low price and ease of use."
If you buy a RAID card with on board cache make sure the cache is battery backed up otherwise a power cut may corrupt your array. Some of the cheaper cards don't have battery backup.
I run a 6x120Gb software raid here. The redundency is nice but when you get that much storage in one place you start having other concerns.
Drive failures are scary. Note, if you're going with a hardware highpoint 1540 controller: forget raid 5. The array takes forever to rebuild (like 4 days) and sometimes fails midway though causing total data loss. (Other people may have different luck though, my friend is doing hardware on 4x160Gb and not enjoying it). I've had 2 drives fail on my software raid and the rebuild went well enough. I suspect the failures were due to inadequate power from the UPS causing a "brownout" condition when my power went off, since both failures happened after a power outage.
So other problems: thats 600Gb of disk space. Nobody in their right mind wants to sit through an fsck, so a journalling filesystem is needed.
but, all the journalling filesystems are new and untested. New your saying? They're a few years old.. and yes, thats true but they're new in comparision to all the other filesystems. And when you're talking about 600Mb of data on one filesystem it really starts to concern you.
(Even so, I've been running raid 5 with journalling on 4 to 6 drives for the last 1.5 years or so and haven't had filesystem corruption)
A friend of mine is running mixed drive sizes in his fileservr and doing no raid. He occasionally has failures and loses stuff, but at least he doesn't lose everything. Still, I'd be pissed if I lost an 80 gig chunk at a time.
The problem with raid is, you gain some redundency but you completely lose the ability to make sensable backups. Unless you're a corporation and can afford $3k for a tape drive (and an additional $500 for tapes) you're faced with the idea of mostly redundent, but no backups. Offsite backups become really appealing, but then you need to shell out the same money for drives that won't be put to use (until something happens)
I still don't have a solution for offsite backups.
As an aside, I started playing with encrypted partitions (not raided). That has the same sort of scaryness. One filesystem screwup and you lose everything. No backups unless you have a second hard drive. Then you're faced with raid 1 which would corrupt both drives, or copying the encrypted volume from drive to drive each night.
I've got no answer for that one ethier, except that encrypting a tape backup would probably be good in a corporate situation.
OK, my own experiences in this area:
I was looking for a basic, cheap RAID system to give me some redundancy.
I got an Adaptec 1200A RAID Controller card, and used two drives in RAID1 mode. This served me well, until I needed more capacity - RAID1 has 100% wasted space.
So I looked at RAID5. I got a Highpoint RocketRAID 454, because it was cheap. BIG mistake. The write performance, on my P4 2.8 Ghz, with three WD1200JB drives, was a terrible 9 Mb/sec, with 80-100% CPU usage. AVOID. I returned it then next day.
Now I have a Promise SuperTRAK SX6000. It's very nice, 25 Mb/s write with only 20% CPU thanks to RISC processor, but expensive.
In summary:
If you want RAID1 only, a nice cheap Adaptec will do fine. If you want RAID5, you will need a reasonable card. Promise do some cheaper ones than the SX6000, with less channels, you could look at those.
Hope this helps!