Zfs send

Zfs is my bug bear at the moment. You can create such wonderfully fast storage for minimal outley.

We use zfs on a range of backup bricks (3x3tb with an atom CPU and 4 gig ram giving about 5.4tb of usable space for $1200 a unit). The main problem I have is how to send data over adsl back to our central storage box (40*3tb in multiple zraid2).

The trick with this seems to be ensuring that you roll back the receivers end first. This allows you to have a clean slate to send to.

More details to come including some source code and diagrams.

ZFS tuning

So a ran across an article that brings up a good point about tuning the ZFS fs (not the pool)

Two options that should probably be turned off by default are:

zfs set atime=off tank
zfs set sync=disabled tank


The sync=disable should only be turned off if you have a log device (ssd or fast spinning disk) otherwise you can end up with corrupt data pools.

Zfs defaults.

So there is a lot of food features in zfs and I find myself deploying it more every day..

One of the bad defaults in my opinion is that it won't automatically replace bad disks with Spares. This can be changed through "zpool set autoreplace on"  but it just seems very silly to me.

Overview

I've resisted the urge to blog for so many years. Now I'm finding it hard to find a place where a sysadmin like me can find various technologies used day to day in the OSS space.

This blog is a list of hacks and scripts and tidbits to do with various technologies that I use day to day.