"John McGaw" said in news:
[email protected]:
Pro: can be somewhat faster.
I suppose if you went to all the bother of setting up RAID but then
foolishly put the 2 hard drives on the same controller then, yes, the
bandwidth available for both drives in aggregate would be only nominally
better. However, if you're going to go to the effort of using RAID, you'll
want to put the drives on separate controllers (i.e., on different IDE or
SATA ports). Then you'll get a near doubling of bandwidth (having the 8MB
buffered drives will also help).
Con: far less reliable: one slight error
on either drive and you've effectively lost the content on both
drives.
Which proves that for a server you don't want to use this configuration.
For home use, and if you have another drive (internal or external) or use
CD-R[W] (although you'll probably want to get a DVD-+RW drive) then striping
is great.
... I'd far rather have mirrored RAID and forego the possible
speed increase in favor of the reliability. Face it, with the size of
modern drives it is becoming increasingly impossible to do decent
backups.
Mirroring a drive is *not* backing it up. You are providing disaster
recovery in case the primary drive goes bad. The mirrored drive has the
same contents as the primary drive, so where are your backups? They aren't
on your mirrored drive. You are "backing up" your hardware when using a
mirrored drive. You are NOT backup up your files in the sense that you have
historical copies from which you can restore.
Rich,
If you really want to go to the bother of using RAID to get a lot better
bandwidth (i.e., effective speed) for your drives, and if this is for
personal use where the box is not critical and there is no requirement that
it always be up (or be able to be brought back up under an hour), then RAID
0 is fine. Just be sure the 2 drives are very similar. Best to get 2 of
the same brand and model. However, as John mentions, you are interlacing
(striping) the data for a file across the 2 drives (unless the file is
smaller than the stripe size) so any file error, surface defect, or other
error in the file renders that file corrupted. Corrupting a file does not
corrupt the entire striped volume anymore than a corrupted file would screw
over your file system now.
If you RAID, you *must* consider how you are going to backup your data ...
unless you consider your data absolutely worthless (and also your time
absolutely worthless to reinstall the OS or applications and redo all the
configurations and customizations). With a DVD-+RW drive, you get a
reasonably capacity on each disc. You get get pretty good storage capacity
on some tape formats, like DLT, but tape is excrutiatingly slow and all
commands are serial. You don't mention what is the size of your current
hard drive (the 8MB you mention is the buffer size). If you currently have
a 120GB drive, get another 120GB drive (same brand and model if possible).
That will give you 240GB striped RAID at twice the bandwidth of a single
drive. But consider that you'll have to buy another 120 GB, or bigger, on
which to store the compressed backups or to save disk images unless you want
to swap a lot of CD/DVD discs or tapes.
For personal use, and although it sounds great to have the potential of
double the bandwidth for drive throughput, few end-user applications would
sustain such a load on the drives. Unless for some reason your "personal"
computer is running an SQL database with huge-sized multiple db files that
are being concurrently accessed by a hundred users, or more, or some such
high disk usage setup, you won't get hardly any noticeable speedup from
using RAID when writing your letter in Word, browsing with IE, or posting in
newsgroups. You must actually have something that will put such a huge I/O
load on your system to make RAID worthwhile.
