Does anyone have experience with SAS2008 based HBA in IR mode with at least two HDDs in RAID 1? Two SSDs in RAID 1? What performance do you have?
I have an LSI 9212-4i4e (SAS2008) in IR mode (P20 FW), currently with 2x Western Digital RE 320 GB drives (first gen I believe) I had left over from an old build.
I first tested them as a VMware datastore (ESXi 6.0), several months ago. Even after they seemed to have finished all RAID 1 initialization (after initialization they were silent during idle, and I let them sit for hours, even days), I was still getting shitty sequential writes (4.5 MB/s writes with dd bs=1m from /dev/zero; 37 MB/s read), and they were audibly (and constant) thrashing during writes.
That was a few months ago. I haven't touched it since, except to change it to pass-through mode. I don't recall if and what performance I saw in VT-d based pass-through.
I did another test tonight, with the HBA in pass-through mode to a FreeBSD VM, and it behaved somewhat better. I reach 12 MB/s sequential write speed with dd (both from /dev/zero and /dev/random) to the device in FreeBSD (unbuffered writes), and 64 MB/s read, from the beginning of the disk. No thrashing for sequential writes. This is more acceptable.
Is the difference down to something that VMware does?
Maybe tomorrow I'll test the VMware datastore performance via an ESXi 6.0 VM, as I don't want to restart the server right now, only to switch the HBA out of pass-through mode.
These are pretty old drives, purchased over 8 years ago, so I don't expect stellar performance. As a reference, a newer, single Western Digital RE4 as a datastore can achieve approximately 18 MB/s sequential writes with dd, even now when it's half full (of non-important data.)
Now I'm looking at options to get it working somewhat better for RAID 1 VM stores, or replace the HBA with a reasonably priced flash cache+supercap RAID controller.
HP P410 512MB FBWC looks interesting, and very cost effective, even if it lacks SATA 3 (and PCIe 3.0) support.
I have an LSI 9212-4i4e (SAS2008) in IR mode (P20 FW), currently with 2x Western Digital RE 320 GB drives (first gen I believe) I had left over from an old build.
I first tested them as a VMware datastore (ESXi 6.0), several months ago. Even after they seemed to have finished all RAID 1 initialization (after initialization they were silent during idle, and I let them sit for hours, even days), I was still getting shitty sequential writes (4.5 MB/s writes with dd bs=1m from /dev/zero; 37 MB/s read), and they were audibly (and constant) thrashing during writes.
That was a few months ago. I haven't touched it since, except to change it to pass-through mode. I don't recall if and what performance I saw in VT-d based pass-through.
I did another test tonight, with the HBA in pass-through mode to a FreeBSD VM, and it behaved somewhat better. I reach 12 MB/s sequential write speed with dd (both from /dev/zero and /dev/random) to the device in FreeBSD (unbuffered writes), and 64 MB/s read, from the beginning of the disk. No thrashing for sequential writes. This is more acceptable.
Is the difference down to something that VMware does?
Maybe tomorrow I'll test the VMware datastore performance via an ESXi 6.0 VM, as I don't want to restart the server right now, only to switch the HBA out of pass-through mode.
These are pretty old drives, purchased over 8 years ago, so I don't expect stellar performance. As a reference, a newer, single Western Digital RE4 as a datastore can achieve approximately 18 MB/s sequential writes with dd, even now when it's half full (of non-important data.)
Now I'm looking at options to get it working somewhat better for RAID 1 VM stores, or replace the HBA with a reasonably priced flash cache+supercap RAID controller.
HP P410 512MB FBWC looks interesting, and very cost effective, even if it lacks SATA 3 (and PCIe 3.0) support.