These are my links for 25 lug 2012 from 14:52 to 15:47:
Disaster: LVM Performance in Snapshot Mode – MySQL Performance Blog – In many cases I speculate how things should work based on what they do and in number of cases this lead me forming too good impression about technology and when running in completely unanticipated bug or performance bottleneck. This is exactly the case with LVM
Number of customers have reported the LVM gives very high penalty when snapshots are enabled (leave along if you try to run backup at this time) and so I decided to look into it.
Netexpertise » Mysql Ultra-Fast Backup with LVM – It is generally good practice to respect the two following points when backing up databases. The backup has to be:
Consistency is easily achieved putting a read lock on all tables beforehands. However, this isn’t always applied, and WILL definately lead to a database integrity problem at some stage.
Once a lock has been set on the database, the backup has to be as quick as possible, all write instructions being held in the queue.
These are my links for 24 lug 2012 from 17:16 to 17:32:
Five Tips for a Better sendmail Configuration – O’Reilly Media – Unix vendors bundle sendmail with the operating system and ship it out preconfigured. It is very easy to install the OS and use the sendmail configuration delivered with the system. Don't be fooled by this apparent simplicity. In the long run, it is better to take charge of your fate. Creating a custom sendmail configuration using current software and features selected for your environment will give you better performance, reliability, security, and maintainability. Here are some tips to get you started on building a better sendmail configuration.
mylvmbackup – mylvmbackup is a tool for quickly creating backups of a MySQL server's data files. To perform a backup, mylvmbackup obtains a read lock on all tables and flushes all server caches to disk, creates a snapshot of the volume containing the MySQL data directory, and unlocks the tables again. The snapshot process takes only a small amount of time. When it is done, the server can continue normal operations, while the actual file backup proceeds.
These are my links for 19 lug 2012 through 20 lug 2012:
Mail server statistics – The statistics are based on completely anonymous information and were performed using randomly chosen IP addresses. When connecting to a mail server defined as an MX in the domain configuration, it can reply in a different number of ways. It may not be online, or may be refusing connections. Also, it is possible that the server does not respond back with a "220" line within the period of time we wait, nor provide a banner that identifies the type of the software running on it, at all times.
Most systems admin is used to setting up the primary mail server, but many of them (like me) are not used to setup a backup mail server in a regular basis. This is my attempt to create a complete document on setting up a backup mail server and testing it for the dooms day. […]
Altering LVM Configuration When a Disk is Not in ODM Anymore – blog’o thnet – If you remove a disk from the system using rmdev -dl hdiskX without having previously reduced the volume group to remove the disk from LVM, and thus have not updated properly the on-disk format information (called VGDA), you get a discrepancy between the ODM and the LVM configurations. Here is how to solve the issue (without any warranty though!).