• Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
    Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.

Actively add disks to a raid array?

Nasty_Savage

Nasty_Savage

Extremely [H]
Joined
Mar 19, 2001
Messages
37,656
Is it possible to add drives and increase disk space to a raid-5 array on an active server? These are Dell poweredge servers, Win2K3. I'm truly pressed for time with other things, but I figured I would ask before I dedicate any valuable research time. Its the same old story, much work and little staff and virtually NO money. Sometimes, I like being an army of one, but this school district is in real trouble from the previous networking neophytes they had here, but they cannot afford additional staff...at least not for a bit...and their money needs to go towards some major infrastructure improvements in the near future. Any thoughts or points in the right direction appreciated.
 
If it's software driven, like it probably is in your setup, I seriously doubt it. I remember at one piont having to do a backup, full-wipe, and reinstall when I needed to add more drives. From my experience, no, you cannot dynamically add more drives to a RAID5.

On the other hand, if you have a good hardware controller, you should be able to add more disks to it without too much trouble. Really depends on whether or not you're using software RAID or a RAID card.

::EDIT:: As a side note, I'm not an expert in this field. You might want to ask in the networking forum, as they are probably alot more familiar with that particular server and it's needs. Weird grey area of which forum to post on, IMO.

::EDIT2:: Or disk storage forum. :) Didn't even know this was here.
 
Even hardware cards which proport to support expanding RAID-5 arrays demand extreme caution when doing so.

Expanding a RAID-5 array is essentially a disaster waiting to happen. If it fails half way through - for whatever random reason - the parity data is partially changed partially not and there's no way of determining what data is correct and what is corrupted. The power could go out, the computer could throw an error, god could decide he doesn't like you...

Ontop of even that theoretically perfect world where the expansion routine is perfectly coded and has no bugs in real life we have the unfortunate reality of BUGS. A single one of these bugs could cause the program to panic and since there's no way to resume the expansion this also means absolutely all your data is lost with no chance of recovery.

Backup your data. Build a new expanded array. Keep your sanity. :D
 
For what it's worth, (I know you said 2K3 and all), linux has a utility called raidreconf that can grow or shrink a raid array.
 
TeeJayHoward said:
For what it's worth, (I know you said 2K3 and all), linux has a utility called raidreconf that can grow or shrink a raid array.
Click to expand...

For crazy people, yeah.

For people who care at all about their data, no. If one of the sectors is corrupted or of a different size - if there are simply a different number of sectors raidreconf will blow up and all of your data will be lost.

Basically, if you want to use raidreconf you should backup all of your data before doing so because it will probably fail. At that point why the hell bother with raidreconf? (it's slow) Just make a new array and move your data back.
 
Doing some prelim research last night, it is suggested that if I can add larger capacity SCSI drives to the array one at a time (hot swappable) then use the diskpart.exe utility, I can extend the Data volume (which is what I want) any thoughts? (yes they are hardware Raids, and the Poweredge servers have hot swappable drives). What do you think? any and all cautions, experiences, etc are welcome.
 
My only suggestion is keep things as simple as possible. The more you throw into the mix doing this the more chance you have for some bad, bad things to happen. Every piece of software used, each piece of hardware swapped is another spot where it can fail for seemingly innoculous reasons. Make sure you've got a good, recent set of backups handy *just* in case.
 
Nasty_Savage said:
Doing some prelim research last night, it is suggested that if I can add larger capacity SCSI drives to the array one at a time (hot swappable) then use the diskpart.exe utility, I can extend the Data volume (which is what I want) any thoughts? (yes they are hardware Raids, and the Poweredge servers have hot swappable drives). What do you think? any and all cautions, experiences, etc are welcome.
Click to expand...

I have done this once, and there is a bit more to it than that.

I put larger drives into a Proliant server, and ended up with twice the space.. but only half the space on the drives was used. The other half of the space was there, but not configured as part of the array, so the RAID controller had to expand the array before SeverMagic (diskpart couldn't I forget why) could expand the partition. So you twice have to run a nail biting routine where one error will bork your data. (once for expanding the array, once for expanding the partition in the array) I was able to do it successfully, but if i had to do it again, I would build new.

What is the server doing? Just file serving?

==>Lazn
 
Hvatum said:
For crazy people, yeah.

For people who care at all about their data, no. If one of the sectors is corrupted or of a different size - if there are simply a different number of sectors raidreconf will blow up and all of your data will be lost.

Basically, if you want to use raidreconf you should backup all of your data before doing so because it will probably fail. At that point why the hell bother with raidreconf? (it's slow) Just make a new array and move your data back.
Click to expand...
It's gotten easier and more reliable with evms; user guide link. Not to say that you shouldn't back up; that's never a bad idea. Just it's not as OH GOD I'M GOING TO DIE dangerous as you're portraying it to be. I'm going to be expanding a 3x300 array to 4x300 (at least) in the near future, with EVMS. I'll be sure to post results.

 
unhappy_mage said:
It's gotten easier and more reliable with evms; user guide link. Not to say that you shouldn't back up; that's never a bad idea. Just it's not as OH GOD I'M GOING TO DIE dangerous as you're portraying it to be. I'm going to be expanding a 3x300 array to 4x300 (at least) in the near future, with EVMS. I'll be sure to post results.

Click to expand...

I'd completely agree if he had been talking about expanding an EVMS2 volume group, which is a totally different ballgame then expanding a vanilla RAID5 array. My array is actually an EVMS2 volume group and expands very well :). He was talking about using raidreconf which even the author admits is only for crazy people and hasn't had a bugfix since 2002...

[QUOTE="The Autor of raidreconf]It is very likely that there are serious bugs that will destroy your data, possibly even on disks not related directly to the array you are re-configuring.

The software is available for download below, and we would like to hear about your experiences using it. But please, keep backups of your data !

The Authour and the Maintainer takes no responsibility what so ever regarding the stability of the software, or even it's usefulness for any particular purpose what so ever. If it destroys your data, we're sorry, but we cannot take any responsibility what so ever for damages caused directly or indirectly in any way by this software, the use of the software, or any other action involving this software.[/QUOTE]
 
I currently have a raid5 on an LSI i4 511 card, and they support extending the raid. and it works too, just takes forever with 250gb drives.

it's done by the hardware.

QM
 
A few questions: What kind of expansion are you looking for? Swap out to larger HDDs, or simply adding in an additional hdd?

What size are the current HDDs? What size drive do you plan on adding into the array?

If you have a Dell PERC card, chances are you can do online expansion by adding in an additional HDD. I have done this in the past with Dell PE servers with no issues.

Otherwise if you want to do a total swap out, you can use ghost to accomplish the task very easily if your running hardware raid and have enough open slots to accomodate both the current drives and the new drives.

Just be sure to have a decent backup and an action plan in case something does go wrong no matter what you do. ;)
 
You must log in or register to reply here.
Back
Top