On Mon, 24 Jun 2013, Craig Sanders <cas@taz.net.au> wrote:
On Mon, Jun 24, 2013 at 06:49:34PM +1000, Russell Coker wrote:
I have just received a free HP DL-385 system, it's quite a nice server with 16G of RAM, 3*SATA and 5*SAS disks.
I want to set it up to run Linux software RAID-1 with Ext4 on a pair of SATA disks for booting and ZFS RAID-Z2 on the 5*SAS disks for data storage.
if you can, use the third SATA port for the RAID-Z array as well - RAID-Z gets better performance when the number of data disks in an array is a power of 2 (e.g. 4 data disks + 1 parity for RAID-Z1, or 4 data disks + 2 parity for RAID-Z2).
The SATA disks will just be for booting. They won't have ZFS because root on ZFS was way too much pain to even consider last time I looked into it. Also I think we are a long way from having ZFS root be reliable enough that I would even consider using it on a remote system with no other forms of boot available. Performance doesn't matter. I'm looking at replacing a system with a pair of 80G IDE disks in a software RAID-1 which is giving more than enough performance.
hmmm...depending on your I/O workload, you might be better off putting an SSD in the third SATA port, partitioned to give you a smallish ZIL (4 or 8GB would be heaps) to smooth out sync. writes, and the remainder as L2ARC cache.
If performance mattered then I'd consider that. However none of my ZFS installations have needed such performance so far, not even the ones where thousands of dollars were spent on storage hardware. Let alone the system that's free.
The problem I have is that the boot disks were wiped, the DVD drive is broken and ILO isn't licensed for remote disk access. This combined with the fact that USB booting apparently doesn't work (it doesn't boot with my usual USB boot device) means that I have to make the SATA disks bootable before connecting them.
can you get the server to pxe boot?
Thanks for the suggestion, I'll give that a go. I had it working a few years ago so I'm sure I can do it again.
Does anyone know what the CCISS disk format is for a single disk RAID-0 (IE a JBOD)? Presumably there is some offset where I can just put an image of a regular bootable SATA disk and have it work.
have you tried just putting a regular bootable disk in?
Yes, then the CCISS BIOS tells me that it found no RAID array and will default to RAID-5 if I don't say anything. Afterwards I configured it for a single disk RAID-0 and one of those options (auto RAID-5 or manual RAID-0) wiped the MBR along the way. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/