RAID question

hi there

which raid mode would allow me too add,change drives without
losing data? i am starting with 4 250 gig drives , i will want
too add more drives and add larger drives(change the 250's too 500
gigs ) eventually , can this be done?

im using a dl533 server mb and a amcc sata 3 controller card
with 4 WD 250 drives too start. this is a storage device just for
storing my data.

"mike6" wrote in message
...
hi there

which raid mode would allow me too add,change drives without
losing data? i am starting with 4 250 gig drives , i will want
too add more drives and add larger drives(change the 250's too 500
gigs ) eventually , can this be done?

im using a dl533 server mb and a amcc sata 3 controller card
with 4 WD 250 drives too start. this is a storage device just for
storing my data.
Any 'RAID' mode, except '0'.
RAID 0, is really a misnomer (since it is not redundant, and hence not the
'R' in RAID), but it gets included because everything else about how it
works, is 'common' to the proper RAID modes.
Which of the AMCC cards?.
What is your application?.
The 'best' mode varies according to the application, and is 'weighted' by
the performance of the card. If this is likely to be anapplication with a
lot of small random I/O (typical database work), then RAID5, is the
primary choice, and will give you 750GB useable from the array. For other
applications, other modes may be better.
Realistically, the best way to upgrade to larger drives will be to backup
the array, and rebuild on new drives. It may be possible to rebuild by
swapping the drives one by one, and then expanding the array, but you are
asking for problems (relying on four rebuilds, and then dynamic
reparticitioning - not a formula for good reliability). On cards
supporting more than four drives, you can instead build a second array,
and clone to this, but most of the AMCC cards only support four SATA
drives.
You do understand, that RAID, is a solution for instantaneous protection
of data against the single failure of a drive, and not a substitute for
backups?. I run RAID, then daily 8mm incremental tape backups, then full
tape archives, and complete hard disk copies monthly, on three rotating
drives, stored in a fire safe, as a 'minimum' for reasonable reliability.
If this is just to 'store data', why fiddle around with the server?. Just
use a NAS device, built for just this job...

Best Wishes

You CANNOT change, add, delete drives in a RAID array, except for RAID 1,
which merely mirrors a drive on one other drive. With four drives, you have
no such options.

--
DaveW

----------------
"mike6" wrote in message
...
hi there

which raid mode would allow me too add,change drives without
losing data? i am starting with 4 250 gig drives , i will want
too add more drives and add larger drives(change the 250's too 500
gigs ) eventually , can this be done?

im using a dl533 server mb and a amcc sata 3 controller card
with 4 WD 250 drives too start. this is a storage device just for
storing my data.

not true

"DaveW" wrote in message
...
You CANNOT change, add, delete drives in a RAID array, except for RAID 1,
which merely mirrors a drive on one other drive. With four drives, you
have
no such options.

--
DaveW

----------------
"mike6" wrote in message
...
hi there

which raid mode would allow me too add,change drives without
losing data? i am starting with 4 250 gig drives , i will want
too add more drives and add larger drives(change the 250's too 500
gigs ) eventually , can this be done?

im using a dl533 server mb and a amcc sata 3 controller card
with 4 WD 250 drives too start. this is a storage device just for
storing my data.

"DaveW" wrote in message
...
You CANNOT change, add, delete drives in a RAID array, except for RAID
1, which merely mirrors a drive on one other drive. With four drives,
you have no such options.

--
DaveW
I'm sorry, but this is wrong.
Proper hardware RAID controllers, often allow dynamic drive allocation,
resizing, etc. etc..
In the 'SCSI' world, it is common on server machines to have (say) a four
drive RAID5 array, and add a couple of new drives, tell the controller to
add these to the array, and let it do the work of recalculating the
parity, and reconfiguring the data. On some 'up market' controllers, this
can even be done 'on the fly', while the array remains 'live' for normal
use.
Don't apply the limitations that are present in most basic motherboard
implementations of RAID, to more serious systems.
However, any system adminstrator doing such an upgrade, would (if they are
wise), backup the data first, and schedule it for a time when the system
can be taken out of use.
The question here is whether this 'medium' controller (up market compared
to the basic software motherboard implementations, but at the 'bottom' of
serious implementations), supports this kind of ability.

----------------
"mike6" wrote in message
...
hi there

which raid mode would allow me too add,change drives without
losing data? i am starting with 4 250 gig drives , i will want
too add more drives and add larger drives(change the 250's too 500
gigs ) eventually , can this be done?

im using a dl533 server mb and a amcc sata 3 controller card
with 4 WD 250 drives too start. this is a storage device just for
storing my data.

Best Wishes

hello there again

ok i have a amcc 9550sx -12 its a 12 port sata 3 controller ,
i beleive it is a very good controller so i should be able to add
drives to my raid with this .

thank you everyone who is replying you are helping me a lot
with this setup. and i am looking to setup a NAS device just too
store my data , the equipment i was given is:

asus pr-dls533 server motherboard w/2 2.0 ghz xenon cpu's
768 megs ram
amcc 9550sx -12 12 port controller card
i added 4 250 gig wd drives and will add more (either 250 or 500 gig ,
hope too eventually have all 500 gig drives)

oh what os is recommended ?


On Fri, 29 Dec 2006 15:37:47 -0500, mike6 wrote:

hi there

which raid mode would allow me too add,change drives without
losing data? i am starting with 4 250 gig drives , i will want
too add more drives and add larger drives(change the 250's too 500
gigs ) eventually , can this be done?

im using a dl533 server mb and a amcc sata 3 controller card
with 4 WD 250 drives too start. this is a storage device just for
storing my data.