Albert Graham wrote:
Joe Tseng wrote:
I saw a few people respond with saying how hardware RAID is overkill
for home use. I had the system drive in my RH9 RAID1 file server at
home die on me last year; although I got a new drive and FC6
recognised the RAID immediately I'm not sure whether my recovery was
due to software resilency or dumb luck. I'm currently working on
gathering parts for a RAID5 file server as a replacement.
1) If a RAIDed drive dies in a soft RAID setup can I assume I can't do
a hotswap?
Don't assume in Linux, because usually anything is possible, it can be
configured so you can hot swap.
2) If my system drive dies again would a new system recognize my RAID5
array?
Of course. (I assume you're not talking about a double fault here!, in
which case you may well loose - see the benefits of raid 6 for this
problem)
3) Does soft RAID5 compare favorably against hware RAID5?
Yes, but it depends on who you ask :) - for any given situation, there
are many arguments, benchmarks to prove which is faster, however, when
you have dedicated hardware (with the right drivers) designed to solve a
specific problem you can "generally" assume it to be better "generally"
- and this is the case with the link that I posted you - not trying to
start a flame war!
Software raid does have advantages over hardware raid, for example, you
can raid loop back devices and test things out without fear of loosing
anything, you can create wide redundant arrays e.g. software raid over
DRBD etc..
If boils down to two thing, 1) Money, 2) Your preference.
Now you either want to spend the time necessary to setup and understand
software raid and its advantages / disadvantages or you want an easy life.
I've used both on many occasions, but I prefer a good hardware raid
controller, I like the idea that data integrity does not rely on my
personal "expertise" or access at the time shit hits the fan, so for
example, if a disk fails I can call the data center and say unplug disk
#2 and plug in the spare disk (assuming no hot spare) thank you boodbye,
I can then head back to the beach :)
Now, I know in your case it is for home use, but hey the link I posted
you was top of the range card for only $300 and it does what it says on
the tin :)
On the other hand lots of people like getting something for free and
software raid gives you that, but your subject was "Raid Card Controller
for FC System" right ?
Albert.
I have looked at this for some time and I have come to the conclusion
that software RAID for most uses are better than hardware raid unless
you have lots of money or need lots of drives.
First, a new motherboard can support many drives. Mine has 7 SATA ports
as well as IDE ports. It comes with software raid but I would still use
the Linux RAID tools.
One issue that I kept coming across about hardware raid is what happens
when your RAID controller dies. Can you get one that uses the same
protocols or do you need to rebuild from backups? I have read enough
articles about someone trying to recover their data after a controller
failure and the replacement doesn't see the data. Even same brand cards.
I finally decided that I would rather use the money to purchase more
drives. :) All the "good" cards were expensive when compared to the
cost of a new system and maybe and extra SATA card. In my case to get a
good RAID controller card required a replacement motherboard anyways.
I have used mdraid (RAID 1) for years and with the last drive failure, I
had one file lost. It was the one that was being written at the time of
the crash. The drive didn't fail, the power supply did.
Next machine is RAID 5.
--
Robin Laing
