Archive
Posts from 2011
Improved ZFS scrub statistics in Solaris 10 update 9
I talked about the ZFS scrub feature a few months back. In the latest Solaris 10 update the developers added additional scrub statistics, which are quite handy for figuring out throughout and estimated completion times: This sure beats the previous output! Nice job team Solaris.
$ read more →Another interesting finding about gluster replicas
In a previous post I talked about my problems getting gluster to expand the number of replicas in a volume. While experimenting with the gluster utilities "add-brick" option I wanted to see if adding two more bricks would replicate the existing data across four bricks (two old, two new), or if the two new bricks would be a replica pair and the two previous bricks would be a replica pair. To see what would happen I added two more bricks: And then checked out the status of the volume: Interesting. The volume is now a distributed-replicated volume, and has a two by two configuration giving four nodes in total…
$ read more →Removing a gluster volume doesn't remove the volume's contents
I made another interesting discovery this weekend while playing around with the gluster volume deletion option. Prior to creating a volume with a new layout, I went through the documented process to remove my volume: I then re-created it using the documented process: Once the new volume was created and started I mounted in on my clients. When I went to access the volume I was quite intrigued to find that the data that was written to the previous gluster volume was still present: Ey? Since 'gluster delete volume' spit out the message "Deleting volume will erase all information about the volume", I figured the contents of the volume would be nuked (never assume, always confirm!)…
$ read more →Some interesting insights on the gluster replicated volume replica value
While playing around with gluster, I had an interesting finding about the way gluster handles replicated volumes. The gluster volume I am using for testing is a replicated volume with a replica factor of 2 (the replica factor determines how many copies of your data will be made). I wanted to add a third replica to my volume, and thought it would be as simple as using the "add-brick" option: Hmmmm -- no go. At first I thought this was no big deal, I figured there was an option or setting I needed to change to increase my replica count…
$ read more →Centos 6 Linux VMs running inside vSphere 4.1 appear to dynamically discover new LUNs
I came across an interesting discovery yesterday while working on a CentOS 6 gluster node. The node was virtualized inside vSphere 4.1 and needed some additional storage added to it. I went into the VI client and added a new disk while the server was running, expecting to have to reboot or rescan the storage devices in the server. Well, I was pleasantly surprised when the following messages popped up on the console: Nice, it looks like the device was added to the system dynamically…
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