I’ve recently switched to the Gentoo Linux distribution (mostly to experiment with this Linux distro) and I don’t regret it so far. This post is about my first impressions about Gentoo.
NFS : see what’s exported from an NFS server
To know what directories are exported by a NFS server, you can use the showmount -e nfs_server from a NFS client.
[root@client:~]# showmount -e server
Export list for server:
/data/dir2 client1 client2 client3
(The /data/dir2 is exported only to specified clients)
Sun Solaris 10 : Creating snapshots with ZFS
ZFS is a great filesystem. Amongst its many features, it has snapshots. Let’s see how to use them.
Continue reading Sun Solaris 10 : Creating snapshots with ZFS
Securing automated rsync over SSH
Quoting the RSYNC homepage : “rsync is an open source utility that provides fast incremental file transfer.”
To make rsync both secure and automated (i.e : non-interactive), you can use SSH as the transport and set up a key pair. This is what will be discussed in this post, along with a few improvements.
OpenSolaris 2008.05 released today
OpenSolaris 2008.05 is released today, you can grab it from the OpenSolaris website.
The distribution is a bootable CD which will let you try it before installing. It includes most of the big hits of Solaris 10 (zfs, dtrace, containers and so on).
If you never tried Solaris or OpenSolaris, this might be a good kick start !
SSH slow to connect to a Solaris 10 host
If you experience a slow SSH connection to a Solaris 10 host while after connection everything works fine, then read on !
Continue reading SSH slow to connect to a Solaris 10 host
OpenBSD : Release 4.3 is out
The twice-a-year release of OpenBSD is out today (More details on Undeadly). You can buy the CD set or get it by FTP (in this case consider donating to the project as CD sales are the main source of income to the project).
CFEngine : Checking for processes
CFEngine can do wonders to keep a cluster in shape, but it can be very useful for a single server as well. Here is a configuration sample to monitor a few common services and restart them should they fail.
Unix : shell tips
I ran into this into the following article, “Learn 10 good UNIX usage habits“. This article is mainly common sense, but there are interesting points, such as :
- avoid piping when you can, in order to save performance (the classical construct grep | wc to count the lines is useless as most versions of grep can count with grep -c)
- use awk to “grep” on a specific field of a line with “… | awk ‘$1 == “XXX”‘ which is cool and I never use
- the find | xargs construct (I’d add “find -print0 | xargs -0”, useful if your find brings back filenames with a space inside …)
All in all it is worth a reading, if only to refresh your memory.
dsh : a distributed shell
A common problem when you deal with a pool of servers (clusters or server farms, you name it) is to execute the same command line on each server. It is usual to solve this with a “for” construct such as :
for i in server1 server2 ; do ssh $i "uname -a"; done
But this is basically re-inventing the wheel everytime. Here comes Distributed Shell (DSH).
Continue reading dsh : a distributed shell