sysadmin

When 99.999% Isn't Good Enough

When discussing availability of a service, it is common to hear the term "Five Nines" referring to a service being available 99.999% of the time but "Five Nines" are relative. If your time frame is a week, then your service can be unavailable for 6.05 seconds whereas a time frame of a year, allows for a very respectable 5.26 minutes.

In reality, none of those calculations are relevant because no one cares if a service is unavailable for 10 hours, as long as they aren't trying to use it. On the other hand, if you're handling 50,000 transactions per second, 6.05 seconds of unavailability could cost you 302,500 transactions and no one cares if you met your SLA.

This problem is one I've come up against a number of times in the past and recently even more and the issue is orders of magnitude in IT. The larger the volume of business you handle, the less relevant the Five Nines become.

Listing ZFS Clones using the origin property

Recently I created my first ZFS clones but quickly realized that there was no simple way to tell the clones from the regular filesystems. My first instinct was to run 'zfs list -t clone' similar to 'zfs list -t snapshot' but this didn't work. Maybe it works in newer versions of ZFS.

Sun Webstack 1.4 - Packages on Crack

I am a huge fan of Sun Microsystems. I love Solaris 10. I love ZFS. I love RBAC. I love zones. I really love T2/T2+ processors. I especially love the T5140 and X4450 servers.

One thing I cannot figure out though, is why Sun lets obviously delirious cocaine addicts package their software. Maybe I'm exaggerating but I think that many will agree that Sun's packages leave much to be desired in general. On top of that, Sun seems to have a constant need to move software around and invent new paths- to boldy go where no sysadmin has gone before????