Hi to all. A question about ZFS pool creation from a FreeBSD guy: I've been always used to create a GPT slice filling the whole physical disk, then reference its GPT label in the 'zpool create' command. But I read here (illumos.org/books/zfs-admin/gavwn.html#gazdp) that the recommended mode is to reference physical disks with the path

/dev/dsk/cXtXdX. Is it still the right way to go with the latest release of OmniOS too? Thanks!

if you just want to use the whole disk, use cXtXdX

Thanks, my primary doubt is about disk relocation within the same controller: in FreeBSD what is named /dev/ada0 today may become /dev/ada3 tomorrow, maybe even just after a reboot... from here the need to reference LUNs in VDEV using their GPT labels, which are persistent across reboots. The same problem does not exists in OmniOS?

i'm not sure i understand

I mean, several SAS and SATA controllers does not show attached disks in a persistent sequence at boot time so, for example, the device attached to the first SAS port won't be always seen as /dev/dsk/c0t0d0, but that name depends by the HDD discovery delay. That's one of the reasons because if FreeBSD I'm used to reference disks using GPT labels

instead of their name under /dev path. But I know that ZFS implementation in illumos is not the same of FreeBSD's one, so maybe this is not a problem in OmniOS?

i've never seen a sata controller do that, so i don't know about sata. but on sas you'll have a wwn and that'll be used for tX in your device name

also, except for some limitations regarding booting from zfs, zfs will generally not care much about device names or device paths when it looks for vdevs of a pool

well, my experience about SAS controllers is a bit different: I have a system with a LSI SAS2008 controller, which unfortunately behaves just like that! :'(

but normally SAS devices have a WWN so that shouldn't be a problem?

Thanks. Actually I didn't installed OmniOS in a server with a SAS controller so far, but I'll plan to do in the future, so I asked.

To get and idea of the matter in FreeBSD: forums.freebsd.org/threads/best-pra…s-vdevs-for-zfs-pools-in-2021.79161

Haven't had a problem with disks changing names randomly, also run mainly SAS, but even manual moving a disk between controllers it properly identifies it because it scans around

oninoshiko: ok, but how can you match the physical drive with the one you see as cXtXdX? At very least in FreeBSD I can assign a label with GEOM to it, which enables me to identify the right disk to be hot-swapped when it has problems. There is a similar way in OmniOS to do the same task?

warden: I record the SN off the drive, then check iostat -En which will list the disk's SN

There may be better ways, but it works for me.

(that said, I think those flags on iostat are specific to illumos based systems. I've not seen it on BSD or Linux)

although, my recent BSD experence has been appliances... so it's like you know that side of things better then I do.

diskinfo(8) can tell you things about the disks as well