Expand RAID-5 disk capacity

[Kunimitsu Kaji]

Hi there,

I'm running Netserver LH-3 with 3x 9GB disk (2 + 1 hot spare) on the on-board NetRAID controllder. 2 logical
drives of C and D is visible on 1 physical drive (18GB) over WinNT4.

Now, planning to add another 9GB disk to expand total disk capacity so that the config. would become 3 + 1 hotspare.
Ideally, I hope NetRaid Assistant will help new disk join to existing configuration without any DB rebuild. Is it possible?

Otherwise, do you have any common idea to add new disk without logical disk change? That is, want to see as if total
disk space of the drive would increase by 9GB (i.e. 27GB).

If it's not good approach, will try make another RAID-0 drive with another logical drive like E.

Thanks in advance for your help.

[Theo Hill_1 · Accepted solution]

Ok first off, if you have 18GB currently, meaning you are either striping the array, or you have 2 single raid 0's, either way you have no redundancy. Why do you have a hot spare? A RAID 5 requires 3 HDD. a 3x9GB HSS RAID 5 will give you a total of 18GB. you lose one drive for redundancy.

[Marino Meloni_1]

hi
you need to explain better what is you actual config,
run into netraid assistant or in Express tool at boot time, and identify (under Object, Phisical drives)the differents disk with they code:
id 0 online A0-0
id1 online A0-1
id2 online A0-2

this is an example of a raid 5, in this case you can ad a disk and have a raid 5 with 4 disk for a total capacity of 27 Mb

the first A0 is menaing the first array, the -X mean the disk number as part of the first array. online, failed, hotspare is the status of that phisical disk.

[Kunimitsu Kaji]

Many thanks for your response.
Current config is exactly same as your guess.

Channel0
+-(0)A0-0-Onln
+-(1)A0-1-Onln
+-(2)A0-2-Onln

Nice to hear that new HDD can join in RAID-5 to be total 27MB size. To make it, should I follow the long process like "full image dump -> RAID-5 reconfig (by Wizard?) -> restore full image"? Or NetRaid Assitan can help me reconfig automatically without any manual backup-restore? (Of course, will take the backup whatever I follow.)

Would appreciate your advice.

[kris rombauts]

Hello Kunimitsu-san,

since the array configuration you provided shows us you have a 3 disk RAID5 and not a hotspare disk like initially explained we'll have to know what you really want :

- do you want to have a disk acting as a
hotspare disk on top of the current
redundant disk configuration ?

I don't think so from your info since you want more capacity so i will assume the scenario below.


- you will add a 4-th disk and include it in
the current array configuration to extend
the logical drive from 3*9 GB to 4*9 GB so
that the netto capacity which is now
2*9=18 GB becomes 3*9GB=27 GB.

- This capacity increase is only at the
logical drive level of the array , this does
not mean you will have bigger partitions at
the Operating System level (NT4 in this case)
You will see a 9 GB free space in NT disk
administrator after the array has completed
the inclusion of the 4-th disk with which
you'll have to work out what you want to do,
i advise to look at the possibilities within
disk management or do a backup of the D:
disk i.e., delete the D: partition and
create a new D: that is just 9 Gbyte bigger.


- You also speak about two logical drives
(C: and D:) but these are you partitions at
the NT level. To avoid confusion, we speak
about logical drives at the array level here
and you only have one which is indicated by
the fact their is only one Ax number ,here
it is A0.


How to add the new disk in Netraid assistant :
---------------------------------------------

- insert the disk
- start Netraid Assistant
- select the new disk (this disk will have the
status 'READY' )
- click on the Logical drive, right mouse
click and select Advanced Menu, then
Add Drive.
- it will ask you if you want to include the
selected disk, choose yes here.

- select the raid level RAID 5 and Apply

Now the extension from a 3 disk raid5 array to a 4 disk raid5 started. It will take approx 45 minutes to one hour i estimate (if the server is not busy during this time).
Done this before and works fine.

hope this helps

Kris

[Kunimitsu Kaji]

Disk expansion was completed successfully last weekend. Thanks again for all your advices.

Special thanks to Kris. You led me to more understanding about RAID and disk config to clear up my worry and confusion. Followed your procedure and it worked perfectly.