MogileFS: realtime device balancing

[brad]

One of the more underplanned aspects of the LiveJournal move was not having enough disks for MogileFS data. We had enough disk space, but not enough spindles

Comments

[dakus]

too bad Mr. MogileFS can't see that little blinky blinky lite on hard disks showing how busy they are...then he'd know what to do!

they still have them lights don't they?

[edm]

Umm, that's pretty much what brad has done. "iostat -x" reports disk accesses (over some recent period of time), and he made that available over the network to MogileFS. Now it can see the "virtual blinking lights".

It's a very cool hack.

Ewen

[dakus]

now I feel all stigmatized!!

Obligatory pun

[xaosenkosmos]

I feel all stigmatized

But edm was the one who had trouble seeing through your comment...

[dakus]

well that's genius then!