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Jeremy Baron:
Also, what do you lose with FreeBSD?
so far I can think of:
- zfs dedupe
ZFS version 28, including dedup, was integrated into FreeBSD head (9-CURRENT) in February. I imagine it will make it back into 8.x eventually, but although dedup is nice on paper, I'm not sure it's actually very useful. You need so much memory to cache the DDT (since putting it on disk kills performance) that it's usually cheaper to just buy more storage.
It's also unlikely that we would ever migrate the /home NFS server to FreeBSD (at least in the near-term future), since it lacks the HA clustering and volume management that Solaris has. (This is an example of an area where Linux *does* have an advantage over FreeBSD.)
It's *also* unlikely that we would ever put /home on ZFS, whatever OS we used. I don't mind ZFS for root, and I use it at home (on both FreeBSD and Solaris) without problems, but we've had some unfortunate issues with it at the TS that have made me a bit wary.
- there's no longer a single "goto" company to get support from
(guessing...) so you lose that annual cost but it may be non trivial to find the right hacker to find/fix a problem in an emergency. of course much of that support is likely to come for free (a guess)
This is true, and is something that came up the last time we discussed this internally. I'm not too worried about this; the login server environment doesn't really tax the OS, and I can't think of many (any?) problems we've had there that would require vendor support.
There are places like iXsystems http://www.ixsystems.com/bsdsupport which offer third-party support for FreeBSD. I don't have any experience with that, or any idea how it compares price-wise.
- you're still a different platform from the rest of wikimedia (basically
the foundation) and so lose economy of scale
Not sure what economies we could gain here. The Toolserver is completely separate from Wikimedia's infrastructure (except that we use the same colo), and both of us prefer it that way. IOW, even if we used Linux, TS systems could not become just another Wikimedia server.
- you mentioned SGE would still be available but it may be unmaintained
(last I checked its enwp article, it said oracle was close sourcing it) just to keep in mind, I wouldn't stay just for SGE
SGE is dead on every platform, including Solaris. The replacement is either Oracle Grid Engine (which costs money), or one of the various forks of the open-source SGE (which should work on both FreeBSD and Solaris). We're still using SGE because I want to see which (if any) fork gains acceptable before switching.
things you lose with linux vs. FreeBSD:
- zfs is gone and (assuming lvm2 + traditional RAID vs. zfs) generally thin
storage provisioning and snapshotting is much more limited and wasteful and fragile/more room for error. also most storage expansions will end up w/ transition periods that have *no* redundancy.
ZFS snapshots are nice, but OTOH ZFS can't remove storage from a pool or do any kind of online relayout, both of which are standard features in VxVM (and I assume in Linux LVM as well, although I have no experience of it.)
In any case we don't store data on login servers.
- zones/jails
Linux has lxc and OpenVZ, which are both very similar to zones, as well as Xen or KVM for full virtualisation.
I haven't kept up with the status in the last ~8 months but debian-kfreebsd may have matured enough to warrant a look. (See #debian-kbsd on oftc)
Never really saw the point of that. If you want Linux, use Linux. (I guess at the moment it's the only way for Linux users to get a useful ZFS?)
- river.