LVM is an implementation of a logical volume manager for the
Linux kernel. The biggest advantage is that LVM provides the
ability to make a snapshot of any logical volume.
In a production environment many users access the same file (file
is open) or database. Suppose you start backup process when a
file is open, you will not get correct or updated copy of
file.
Read-only partition - to avoid inconsistent backupYou need to
mount partition as read only, so that no one can make changes to
file and make a backup:
# umount /home
# mount -o ro /home
# tar -cvf /dev/st0 /home
# umount /home
# mount -o rw /home
As you see, the draw back is service remains unavailable during
backup time to all end users. If you are using database then
shutdown database server and make a backup.
Logical Volume Manager snapshot to avoid inconsistent backupThis
solution will only work if you have created …
In the previous part of this article, we had a look at how to
configure LVM, and we had successfully setup a Volume Group and
two Logical Volumes. Now we are going to have a look at extending
the group and volumes.
So let’s start the story from the previous part of this
article!
Because, the mysql
volume was filling up quickly so
I decided to add a new disk of size 10 GB, and I really want to
extend the mysql
volume quickly, before the MySQL
server stalls. With LVM, thats no longer an issue.
Partitioning the new diskFirst let’s have a look at the partition
table,
$ fdisk -l
The new disk is /dev/sdb
, but its not partitioned,
so lets create a single partition spanning the whole disk.
We will do so using the fdisk utility,
$ fdisk /dev/sdb
which will provide you with an interactive console, that you will use to create the …
[さらに読む]
Linux LVM (Logical Volume Management) is a very important tool to
have in the toolkit of a MySQL DBA. It allows you to create and
extend logical volumes on the fly. This allows me to say, add
another disk and extend a partition effortlessly. The other very
important feature is the ability to take snapshots, that you can
then use for backups. All in all its a must have tool. Hence,
this guide will allow you to understand various terminologies
associated with LVM, together with setting up LVM volumes and in
a later part will also show you how to extend the volumes.
But first up let’s understand various terminologies associated
with LVM.
TerminologiesThere are three terminologies that you need to be
familiar with before you start working with LVM.
- Physical Volume: Physical Volumes are actual hard-disks or partitions, that you normally mount or unmount on a directory.
- …
ある日、オフィスに行くとキムラデービーの木村さんに面白いマシンがあると言うので見せて貰った。
マシンと言っても、小さい白い箱からプラグがニュッと出ているだけである。そう、一昔前に話題になったあのSheevaplugである。
Sheevaplugはニュースで見て知って居たが、実物を見るのは初めてだ。とはいっても、実際に稼働しているものを見たわけではなく箱から出したばかりのものを見せて貰っただけである。実物を見た第一印象は、軽い!小さい!の一言だ。この小さな箱でサクサクとUbuntu …
MyNAのメーリングリストで迷ってる人を見かけたのだが、意外と同じことで悩んでいる人が多いのではないかと思って書いておく。
MySQL
Clusterのダウンロードページに行くと、Linux用のRPMが細かく分かれていて、どのパッケージをどのホストにインストールすればいいのか迷ってしまうんじゃないだろうか。MySQL
Clusterには管理ノード、データノード、SQLノードの3種類が存在するが、それぞれにインストールしなければいけないRPMは次の通り。
管理ノード
- Cluster storage engine management・・・ndb_mgmd(デーモンプログラム)が入っている。
- Cluster storage engine basic …