How can I increase disk space on a RAID 5 server with no slots left?

Yes, it can be done, but having 8 drives in one raid 5 is a little bit risky.

In my experience, the drives will still wind up as 146Gb drives (one by one). At least on Server 2003 with hardware RAID 5, you cannot increase drive space with bigger drives. ... Thinkpads_User

ty_young_99: It would probably be much easier (but a bit more expensive) to add a Storage Server to your network. Server 2008 can act as a Storage Server - I have one running at a client and the purpose was to add disk space.
... Thinkpads_User

That what I was afraid of.   I guess that's my real dilemma. Does the HP ACU let you take advantage of the additional space after the drives have been installed?  Otherwise its all in vain.

Yeah, storage server's out of the question.  I have good backups and all, but restore from tape takes forever.  Good for disaster or recovering a few things but not a Terabyte.

The RAID controller will build to the original limit and the rest of the space is just wasted. No system would ever know about the additional space because it is not registered to anything. ... Thinkpads_User

If a storage server is out of the question, you may need to buy a new server with much more space to begin with. Also, if doing that, plan for yet more space down the road.  ... Thinkpads_User

As already advised you can't expand your existing raid 5 array. Have you considered adding a Direct Attached Storage solution to the server?

I think I may have found my answer in another posting titled INCREASE RAID 5 SIZE.  According to Compaq Engineer, this can be done and sharkbot221984 actually did it successfully.  Now all I need to know is how?

You will also need this user guide - look at page 35 at Extend Logical Drive
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00294139/c00294139.pdf

So replace all drives one at time, every time wait for rebuild to finish, extend the logical drive using ACU, expand or create new partition in windows 2008 server

Sorry typo - Extend Logical Drive is on page 25.

You can certainly replace one at a time and finally realise the extra space but look at how long you will be without parity. It used to be a useful option with 9GB, 18GB disk sizes as rebuild was fairly fast, but with 146GB disks you're talking at least a day to rebuild each time so the chance of encountering a disk failure or bad block increases. Can you afford a couple of weeks with the extra risk of effectively having RAID 0?

I'd be more tempted to add a MSA 50 or MSA70 external shelf plus P800 controller, you can move the cables from the current controller to the P800, then you have the 8 internal plus 10 (or 25) external bays to play with. Since the MSA50, MSA70 and P800 have been superceded with a new generation you could buy quite cheaply.

About $350 for the controller, and $600 for the enclosure off ebay, may be second hand but not like you're buying second hand disks, the shelf works or it doesn't so doesn't matter that it's not brand new.

So why is having 8 drives in one RAID 5 risky?

The more drives you have in one RAID 5 array the more chance of a second disk failure during a rebuild, also the higher the capacity of those disks the more chance of an unrecoverable read error on a disk during a rebuild. The controller does check it can read the drives properly and repairs any read errors during background parity check but that's only when it's idle. It would be safer to use RAID 6 (ADG), then you can suffer two drive failures without it crashing, but the performance is worse than RAID 5 and you would have to buy the Smart Array Advanced Pack and possibly a larger cache module to enable RAID 6.

And when you buy a server, frequently you get disk drives from the same series. I had cases when two drives from same series failed soon one after another. That is why I do not use single RAID5 array on more than 5 drives.

The need of upgrade depends on controller model you have. HP DL380G5 comes with this three models. Only the first one supports RAID6 as it is.
- Performance Models: HP Smart Array P400/512MB BBWC Controller (RAID 0/1/1+0/5/6)
- High Efficiency and Base Models: HP Smart Array P400/256MB Controller (RAID 0/1/1+0/5) - Available upgrades: 512MB battery-backed write cache (BBWC) or standalone battery for RAID 0/1/1+0/5/6
- Entry Models: HP Smart Array E200/64MB Controller (RAID 0/1/1+0) - Available upgrades: 128MB battery-backed write cache (BBWC) for RAID 0/1/1+0/5

You're right, it's the P410 that needs advanced license for RAID6, not P400.

This is great, it's just what I was looking for.  Thanks for all your help and for the advice as well.