I'm trying to get ESXi 5.5 installed on a RAID 1 set of Western Digital 2.5" Red Drives on an SAS2008 controller. The problem I'm running into is that some part of the stack doesn't seem to realize that these drives are advanced format drives and the various partitions the installer creates aren't properly aligned.
Any suggestions on how to force the installer to properly partition the drive?
Software RAID controllers are not supported by ESXi. If you plan on running an onboard RAID system, you'll need to install a hardware RAID controller. Either Adaptec or LSI brands would be a good place to start.
I see two problems in your configuration:
1. According to this list, ESXi/vSphere does not have native support for "4k" disks. I'm not sure if it is true, but if so, then it is working with 512B sectors (which drives "pretend" to have for backward compatibility) but is not aware of underlying 4kB-format. I doubt there is any way to "force" ESXi to align partitions correctly, on 4kB-boundaries. You could do it maybe manually before ESXi-installation, with disk-partitioning tools and a little calculation. But I'm not sure if ESXi just formats partitions, or removes them and creates new...
2. LSI SAS2008 is very basic "entry-level" raid-controller, not good for ESXi. It supports only raid-0/1/1E/10, and no on-board cache. You will get very low i/o performance with it, because ESXi unlike other modern OS does NOT do disk-caching and relies on controller.
A side note:
WD "RED" does not have constant rotational speed. I would never recommend such drives for raid, as they get quickly and frequently "out of sync" (drives in raid-array do not "talk" to each other, so one drive might be rotating faster than the other). Moreover, that "IntelliPower" technology is very aggressive power-management. It even turns off drives frequently to save some power, but again, this is not good for raid. WD writes "it is designed for NAS and RAID" but my own experience is different. Some "paranoid" raid-controllers even mark such drives as "failed" very easily...
Thanks for the comments.
1. From what I can tell there is at least some support for 4k disks in 5.5, at least it seems to know enough that if you create a datastore on a 4k disk it does the right thing partition wise. Installs though don't seem to work right, but like you said might be possible to manually format and install, though with I think 7+ partitions that get created on an install I don't think its worth dealing with.
2. The SAS2008 is basic, but also very cheap and actually works really well as a passthrough controller for ZFS in IT mode. I have two in this server, one in IT mode as passthrough and another in IR mode for booting and the datastore. The boot controller seems to work fairly well with a couple small SSDs in there, but not with any traditional disk drives, could be a caching issue like what you are pointing to.
Re Side note:
For whatever its worth I have 6 of the 3.5" Red Drives hooked up as ZFS raid-z2 setup and haven't had any issues with them over the last 6+ months. For a home server the price + 3 year warranty was enough to make me give them a try. For something more mission critical I would've gone with something else.