I’m trying to help an organization with adding some drives to a pre-existing Raid5 configuration to a Linux server but I’m missing a step somewhere. Here’s the situation..

The server is a Dell R510 running Red Hat 6.2. There is a pre-existing Raid 5 configuration using a Dell Perc H700 controller. 3 drives make up the Raid 5 – ST3600057SS drives configured using Dell Openmanage. At a later time they purchased 2 additional ST3600057SS drives with the intention of adding them to the pre-existing Raid 5 setup. Drives were inserted and apparently configured/added to the Raid 5 using Openmanage but this additional storage is not seen with pvdisplay. This is all prior to me –

What I see now is pvdisplay apparently shows the Raid 5 available but not including the 2 new drives – shows a little over 1TB available (I would expect to see more). The web interface to Openmanage shows 5 drives make up the virtual storage – as Raid 5. The original 3 physical drives show a nice “green” status, the 2 new drives show a “non-critical” status. From googling, “non-critical” status means the drives are not certified to use but generally are ok. Also Openmanage shows space available is 2233gb and are part of sda (/dev/sda). Each physical drive show available space of 558gb – math tells me we have 4 drives and 1 parity drive. So according to Openmanage, we have a 5 drive Raid 5 going on. But pvdisplay apparently still just sees the original 3 drive Raid 5 (or at least the space for it).

We also booted the server and got into the Bios/Perc controller card configuration. At that level we see all 5 drives – all 5 appear to be healthy.

Fdisk shows for sda (for partition sda5 which is the partition used) we have 1165341696 blocks.

What steps am I missing so pvdisplay sees the newly added drives in the Raid 5 for sda? As I’m writing this, I’m thinking there is something in Openmanage I need to configure – I think there is a “configure…” pulldown somewhere in Openmanage I need to do..?

Of course you'd want to be sure to have a good backup before doing anything just in case. Having said that...

If OpenManage shows the logical drive (RAID set) has the space of all the disks (minus parity) then you are done with the PERC setup. Be sure you're only seeing one logical drive. It's possible with PERC to create more than one RAID set and if they'd done that OpenManage would show you more than one logical drive.

Next you'd want to verify /dev/sda (assuming from your comments that is what has the PERC presented LUN) sees all the space. (It won't be exactly equal to what you see in OpenManage but should be approximately the same). Use fdisk or parted to see that.

Next question assuming sda sees it all is whether sda is partitioned. (i.e. Is your PV in your VG using /dev/sda itself or one of its partitions such as /dev/sda2?) If using a partitions you'd have to expand the partition using fdisk or parted. Note that often even when using an entire drive it is done with the first partition, e.g. /dev/sda1, rather than the overall drive, /dev/sda, so you might need to expand sda1. You don't say if this is a boot drive but if it is usually you're going to have at least 2 partitions - one of them being for /boot and the other being for LVM.

Once you've resized (expanded) the appropriate partition you need to resize the LVM Physical Volume (PV) using the pvresize command. You'd then check the LVM Volume Group (VG) to make sure it sees the new space of the PV.

After VG has the space you can either use lvextend the resize the LVM Logical Volume (LV) that you want to expand or use lvcreate to create additional LVs. If you expand an existing LV you'd then need to resize the filesystem or if you create new LVs you'd need to layout new filesystems.

Thanks for the reply -- Im following everything you are saying but you got my attention with might needing to expand sda. From what I recall, there is a /dev/sda1 for the boot partition. There was an sda2 and sda3 for some other partitions with /dev/sda5 being used for LVM (/dev/sda5 is one I would want to expand). Ill see if I can get the output of a fdisk l /dev/sda to tell me what we have there.

sda5 would be part of the extended partitioning. You have only 4 partitions usually but can use the 4th for extended partitioning for more. I neglected to mention with partitioning you sometimes have to adjust other partitions if the one you're interested in isn't the last one or if the space you want is all in an earlier one. From what you just wrote it sounds like partition 5 is your last one and hopefully all the space is available to add to that so you may be able to just extend it. If you have partition 6 and/or more beyond that you'd have to adjust space in those starting at the end to free up space because the partition layouts are contiguous space on the disk (LUN).

See below for the output of a fdisk and pvdisplay. fdisk does show the 2.3tb of space and pvdisplay shows the original ~1tb. So yes we are done with the Perc controller like you thought. I'm going to try to recreate this fdisk partitoning in a test VM I have and see if I can expand sda5. I'm open to any suggestions --

fdisk -l /dev/sda
Disk /dev/sda: 2398.2 GB, 2398202363904 bytes
47 heads, 36 sectors/track, 2768315 cylinders
Units = cylinders of 1692 * 512 = 866304 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5790ab87

Device Boot Start End Blocks Id System
/dev/sda1 2 243 204732 de Dell Utility
/dev/sda2 244 6441 5243508 c W95 FAT32 (LBA)
/dev/sda3 * 6442 6684 204800 83 Linux
/dev/sda4 6684 1384158 1165342720 5 Extended
/dev/sda5 6686 1384158 1165341696 8e Linux LVM


pvdisplay
--- Physical volume ---
PV Name /dev/sda5
VG Name VolGroup00
PV Size 1.09 TiB / not usable 13.00 MiB
Allocatable yes
PE Size 32.00 MiB
Total PE 35563
Free PE 1894
Allocated PE 33669