…thing, it has a lot of information on the box’s hardware, including RAID controllers, …a pretty good idea what hardware and operating system I’m working with. System performance Next I investigate what the system is doing…this is from some ORM system, such as Class::DBI, which does $dbh->ping before…
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 15 Comments
…. What is IO alignment I would like to start with some background on IO alignment. So what is IO alignment and how does a misaligned IO look like? Here is one example of it: In this case the RAID controller… the RAID has 4 bearing disks (spindles) and if there’s a misalignment on the file system, you can see how RAID ends up doing…
Post: Recovering Linux software RAID, RAID5 Array
August 27, 2011 By 2 Comments
… generic Linux server. When you restart the system RAID5 volume which has more than 1 …a way to do it. It could be by design as using such commands wrong way can ruin your RAID array. What you can do…/c/c mount: special device /dev/c/c does not exist ReadyNAS1:/# lvdisplay — Logical volume — LV …
Post: How reliable RAID really is
June 30, 2006 By 11 Comments
…RAID with two failed hard drives. The impression is it should never happen (while it does…. What one would like to do …system and MySQL database is good idea. So my story had a…RAID is more reliable than plain disk, RAID6 is more reliable than RAID5 but all they can fail, even expensive SAN systems…
Post: Setting up XFS on Hardware RAID -- the simple edition
December 16, 2011 By 9 Comments
…System /dev/sda1 2048 7813119 3905536 82 Linux swap / Solaris Partition 1 does…a remainder, then our partition would not start on a RAID stripe boundary. Create the Filesystem XFS requires a little massaging (or a lot). For a…
Post: Rendundant Array of Inexpensive Servers
August 21, 2008 By 15 Comments
…does not affect your system and also what you can recover from server failure easily So you should assume every component in the system…on RAID system even if you’re running RAID6 with couple of hot spare. The RAID … normally do not use it because it a large waste, especially as most of systems have …
Post: Living with backups
November 6, 2008 By 28 Comments
…What does it all mean? There is a clear conflict between the regular database activities, which need fast response times, and doing…system must be using CFQ elevator algorithm, it does not work with others. But that is not really a problem since most modern systems…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 6 Comments
… but what is the most important they often come with a need of…”small” batch job being ran which does a lot of updates can also be… through xtrabackup or LVM snapshot, RAID controller doing RAID validation, some centrally kicked of…system you should be able to see it by comparing IO MySQL is doing…
Post: RAID and Scale Out Discussions
June 12, 2007 By 3 Comments
…system is needs to growth and how much effort people would like to spend on the infrastructure because this defines a lot what…RAID for their MySQL installations. I surely agree with Jeremy on Commodity does not mean Crapy thing. There is usually a…Opteron servers. They also do not provide high volume…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
…A question is why to use a flash memory at all, when a battery-backed disk controller write-back cache does…is battery backed up just as RAID cache so it can handle system restarts. When putting log …through the adaptive hash index! What is your database like? Do you have a big enough buffer pool? PZ…
