Most admins have probobably encountered a situation where someone says “hey this really bizarre thing is occurring.” Whenever I am approached to look at these types of issues I will typically start by jumping on my systems and reviewing system, network and performance data. Once I’ve verified those are within normal levels I will begin [...]
Linux NFS server implementations export a number of statistics through the /proc file system. The nfsstat utility can parse this file and display various performance counters, and the data that is displayed comes from the /proc/net/rpc/nfsd proc entry: $ cat /proc/net/rpc/nfsd rc 0 2585 290 fh 0 0 0 0 0 io 1069882 10485760 th [...]
As an admin, there is nothing worse that the feeling you get when you determine you are dealing with file system corruption. Wether it’s a lost inode or a corrupted superblock, I always get a big knot in my stomach when I figure out that corruption exists. With modern file systems like ZFS it’s trivial [...]
Storage management, the joys! Storage administration is one of those tasks that every admin does, and depending on your growth it may be something that consumes a lot of your time. If your servers are connected to a Fibre channel or iSCSI SAN, you probably need to periodically poke your systems to see new storage [...]
I’ve been fascinated with I/O and file system performance for years, and chose prefetch.net as my domain name after reading about pre-fetching algorithms in the book UNIX file systems (a great book that I need to read again). Since most applications access data that is not laid out sequentially on a hard drive platter, seek [...]
In a previous post I shared the research I did on the various NAS solutions that are available. I’ve been experimenting with the software solutions I described in that post, and have decided to forego a pre-built solution in favor of a DIY project. There were a couple of reasons for this: 1. The hardware [...]
