Hello Miles,
I did research the matter about 18 month (or maybe 2 years) ago for the
business, even asked the list. Decided in favor of FreeNAS (based on
FreeBSD+ZFS if someone doesn't know). Can't tell how it went because the
project died for reasons unrelated to the storage.
If you decide to go with OpenBSD I'd strongly suggest to use a good
hardware RAID controller (not relaying on the softraid). Make sure it's
supported. I've had a good experience with HP Smart Array Pxx series. You
can buy older models quite cheap on ebay (if you trust ebay). Haven't
checked it on a "generic" PC though. Install the battery and replace it
than the system complains (on boot or otherwise) - also sold on ebay.
RAID5 might not be enough than dealing with "few terabytes" - there is a
risk of a second disk corruption due a high activity during recovery
(google the subject). Consider RAID6 or RAID10 (1E, 1C, etc.) - both
require a minimum of four disks.
I was told that fsck requires about 1G of memory per 1T of space. Could
be dealt with by splitting to multiple partitions (labels). The ZFS memory
requirements aren't lower anyway.
You need some sort of snapshoted (!) backup. Even if the RAID saves you
from the disk corruption (the "if" here bigger than most people think), a
human error (or a virus on someone's computer/phone) can destroy all your
data, and than a rsync can propagate the "changes" to the backup (also
destroying it if you don't have proper snapshots). The snapshots don't need
to be called "snapshots" - any sort of backup with possibility to restore
to an older date will do.
Wednesday, July 20, 2016, 6:52:04 AM, you wrote:
MK> Got a fileserver with a few terabytes of important personal media, like all
MK> old home movies, baby photos, etc. Files that I want my family to have
MK> access to when I die.
MK> Really it's more of a file archive. A backup. Just rsync + ssh. Serving
MK> it isn't the point. Just preserving it forever.
MK> (It's all unencrypted. It's not that kind of private. Private and offline
MK> from the outside world, but public within the family.)
MK> For years it's been on a Synology, Linux ext4 filesystem. Now I'm making a
MK> new clone of it (new PC) to be in a different location.
MK> I assumed I'd use FreeBSD + ZFS because of ZFS's checksum features. But
MK> really I love and prefer OpenBSD for everything else, and don't want any
MK> other ZFS features : just that checksum.
MK> So I figure if I use OpenBSD + softraid RAID 5 (across 4 disks) and then
MK> write my own little shell script to track the MD5 (find . -type f -exec md5
MK> {} \;) whenever I make changes, that should be enough to see if a file has
MK> been changed due to disk corruption.
MK> (Which makes me realize I don't know a damn thing about disk corruption,
MK> only that it's happened a few times in the past. The occasional JPG or MP3
MK> from the late 90s that used to work but now doesn't, and who-knows-why.)
MK> Before I embark on this direction for a fileserver, I thought I should
MK> check with the smart people here on misc:
MK> Any tips from anyone who's done something similar?
MK> Or would anyone advise me against OpenBSD or this MD5 log approach for a
MK> fileserver like this?
--
Best regards,
Boris mailto:psi...@prodigy.net
