comments on newfs raw disk ? Safe ? (7 terabyte array)

[Ivan Voras]

Arone Silimantia wrote:

> dd if=/dev/zero of=/dev/da1 bs=1k count=1
> newfs -m 0 /dev/da1
> mount /dev/da1 /mnt
> 
> And that's that.  But it seems too good to be true!  Can someone please 
> comment on this scheme and if there are some hidden dangers or lack of 
> functionality that I will regret in the future ?

No dangers at the system level - you can create your file system on any
storage-like device, use it and mount it any way you want. Raw disks are
a perfectly valid target.

> Will it fsck just like any other UFS2 partition I run ?  Can I run 
> quotas and snapshots and everything else on it, just like normal ?

Yes.

> Other than the fact that I can't boot this, is there _any downside 
> whatsoever_ to newfs'ing raw disk like this ?

Only "collateral" problems because of the partition size: a regular
(non-softupdates) fsck will take a LONG time to finish and eat a LOT of
memory while it's doing its stuff. You'll need a lot of swap space (1GB
per TB? someone had empirical numbers on this, I'm sure) if you think
you'll need to fsck it entirely. Creating snapshots will also take a
long time on it, and you probably want to search the lists for
recommendations about creating snapshots in a second level directory in
order not to block the root directory. Related to this is
background-fsck which works by creating snapshots, so you'll probably
want to disable it.

In any case, try every feature you think you'll need before deploying it.

Also, write about your experience on this list :)