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Is RAID 1 a Step Forward or Backward?

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December 10, 2007 12:08:49 AM

I'm currently utilizing a 6-year-old Dell Dimension 4100 (866MHz Pentium III, Windows XP2) as
a file server to back up my two other PCs on a 100Mbps LAN. I basically just run daily incremental image backups to a 300GB IDE drive using Acronis True Image Home Edition V11. I also like to store a few 'historical' images (1 week ago, 1 month ago) because it allows me to restore old configurations (a protection scheme which has saved my butt a few times).

I'm planning to get a larger drive to accomodate increased storage needs, and also to open up the option of creating some shared folder space for media files. GIven this, I'm thinking about adding a RocketRaid 1520 SATA RAID controller card (http://www.newegg.com/Product/ProductReview.aspx?Item=N...) to the Dell,
picking up two 500GB Seagate SATA drives, and then running them in a mirrored (RAID 1) configuration.

Two questions.

(1) Is doing this more trouble than it's worth? Is adding such a RAID controller card likely to be a hit-or-miss proposition with such an old computer? Speed of backups is not much of a concern as I run these backups overnight. What IS a concern is if the RAID 1 controller actually REDUCES reliability - i.e. increases the possibility of corrupted backups. I've been reading a lot about NAS devices and it seems like a lot of them suffer from this.

(2) Are mirrored drives (RAID 1) IDENTICAL in format to a standard, non-RAID drive? In other words, could I pop one of the mirrored drives into another PC with a non-RAID SATA configuration and access the files?

(3) Would I be better off purchasing a dedicated NAS device with a RAID option?

For those of you who might suggest it, I have considered and rejected purchasing a Windows Home Server device at this time. I don't believe the software is sufficiently baked (read the Microsoft forum on WHS and judge for yourself) and it's a LOT more expensive than simply adding a RocketRaid controller to the Dell.

Any advice would be appreciated.



December 10, 2007 2:26:10 PM

1) Assuming you have good hardware (i.e. nothing wrong with the RAID card, the hard drives, or your existing system), and buy the RAID card from a reputable manufacturer, and install it properly, it should be very reliable. Check with the RAID card manufacturer regarding compatibility with your system - there are some system BIOS's that may have difficulty with certain cards, especially with the difference in age between your system & the proposed RAID card.

2) Most RAID 1 controllers write the individual drives of a RAID 1 in a format that enables them to be read as stand-alone drives without the RAID controller. To make sure yours does, create the RAID 1, dump a few files on it, then take one drive out and put it in another computer and make sure they can be read. When you put the drive back in, you need to delete and re-create the RAID volume, partition, and format it to make sure they're back in sync.

3) The think I don't like about stand-alone NAS units is the total lack of performance (some are slower than molasses), and relatively cheap/consumer quality of the software. Bad RAID software is worse than no RAID because it lulls you into a false sense of security. I've seen NAS's set up in a RAID 1 where one drive failed, and the data on the remaining drive became inaccessible. Wouldn't rebuild the RAID either. Nice protection. :sarcastic: 
December 11, 2007 12:33:38 AM

Thanks so much, SomeJoe777. I fully appreciate your comment about performance of stand-alone RAID devices. Most appear to have significantly less horsepower than my six-year-old PC. And the performance they quote is one-third what I currently get (though admittedly I'm not running in a RAID configuration).
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July 11, 2008 10:11:55 AM


Quote:
Thanks so much, SomeJoe777. I fully appreciate your comment about performance of stand-alone RAID devices. Most appear to have significantly less horsepower than my six-year-old PC. And the performance they quote is one-third what I currently get (though admittedly I'm not running in a RAID configuration).


A file server (or NAS) doesn't need horse power. The processing bottle neck is the read/writes from the hard drive. Since the CPU is virtually never utilized, a 386 would probably sufficiently handle the load. Memory can have an advantage when you're repeatedly reading the same files, but when reading from a large diversity of files memory becomes useless too.

The only horespower an NAS or file server needs is in the hard drives.
July 11, 2008 4:11:48 PM

Duke of Veg said:
A file server (or NAS) doesn't need horse power. The processing bottle neck is the read/writes from the hard drive. Since the CPU is virtually never utilized, a 386 would probably sufficiently handle the load. Memory can have an advantage when you're repeatedly reading the same files, but when reading from a large diversity of files memory becomes useless too.

The only horespower an NAS or file server needs is in the hard drives.


The hard drive read/write rates are absolutely not the bottleneck.

Typical hard drive read/write speed: 80 MB/sec

Most standalone NAS units read/write speed over the network, using Gigabit Ethernet: 8-10 MB/sec

Windows Server, even on a light processor (think Pentium 4 2.4 GHz), read/write speed over the network, using Gigabit Ethernet: 35 MB/sec.

The bottleneck in the standalone NAS units is not the hard drives - it is the processing power in both the network subsystem and the SMB code (same as it is in Windows servers). A cheap, several-year old Windows Server will run circles around the standalone NAS units from NetGear, Linksys, D-Link, etc.
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