… things block against them. If you create a RAID volume over many EBS volumes, you are more likely to be affected by…. As a result, if you’re going to build a big database in the Amazon cloud platform, bigger than a single… of key advantages at the technical level. These include EBS volume snapshots, for example. They work much better than LVM snapshots…
Comment: Disaster: LVM Performance in Snapshot Mode
February 9, 2009 By 55 Comments
… fragmentation. The traditional filesystems use COW technology on various levels – volume manager (LVM, VXVM) or in the filesystem (VxFS). If you… compared it with xfs. The difference with LVM snapshot is big. “randomio” opens its target with O_DIRECT and does random… ~]# lvcreate –size 60g –snapshot –name snap /dev/VolGroup20/mysqldata Logical volume “snap” created 1379.3 | 1104.6 0.1 68.7…
Post: Death match! EBS versus SSD price, performance, and QoS
February 21, 2011 By 54 Comments
… they behave. Are the theoretical advantages of SSDs really a big advantage in practice? I will show the performance of two… week and now, they went from a 10-volume array to a 20-volume array, for example. But the samples I’ll…. Note how variable the quality of service from these EBS volumes is — some are fast, some are slow, even though we…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… commands are for giving me information about LVM devices, volume groups, and logical volumes. At this point, unless I’ve seen something… Peter worked with the client 6 months ago, you have big shoes to fill, and getting further gains will probably not… occasionally something really bad that can be fixed and bring big gains. Schema, query, and index optimization Analyzing and optimizing a…
Post: Small things are better
October 8, 2006 By 15 Comments
… never happened – this was decent PowerEdge 2850 box with RAID volume, ECC memory and reliable CentOS 4.4 distribution but still… maintenance with them it will take less times. Smaller RAID volumes would typically rebuild faster, smaller database size per system (yet… to several servers will likely be easy than splitting one big one. There are bunch of complications with many tables of…
Post: Data mart or data warehouse?
July 15, 2010 By 13 Comments
… difficult to build such a model that scales as the volume in the warehouse increases. For this reason OLAP analysis usually… star schema, particularly as the volume of data in the database increases. So what is the big deal? From a OLAP performance… on a snowflake or fully normalized schema at data warehouse volumes. This is in large part because commercial database software supports…
Post: How reliable RAID really is
June 30, 2006 By 11 Comments
… size storage on each node. At least multiple smaller RAID volumes could be used so rebuilding any of them takes less… the RAID BIOS itself or RAID tools ? Should not be big deal especially for offline drive. Backups with Instant recovery – could… is gradually restored in the background back to the local volume. Local Networks are fast these days so it could perform…
Post: Using XtraBackup on NFS for MySQL backups
December 9, 2010 By 5 Comments
XtraBackup works great for backing MySQL up to an NFS volume, but there is a gotcha that you need to be…, and then use a different server that also mounts that volume to prepare the backup (apply the logs), that other server… for general-purpose usage, but it should not be a big deal for xtrabackup. This and lots of other details about…
Post: Shard-Query adds parallelism to queries
November 15, 2010 By 16 Comments
… query into something more like OLTP. Instead of getting one big chunk of data in one query, it runs many smaller… things get slower as the query has to examine larger volumes of data. Regarding the performance of Shard-Query, this machine…-Query will perform much better than regular MySQL as the volume of data grows. Remember that this workload fits entirely in…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…-demo-data-flatfiles 30GB ext3 EBS This is an ext3 volume which contains the flat files for the demos, if you… shard contains only 128MB of data! Storage engine makes a big difference In general, a column store performs about 8x-10x… for queries which access a significant amount of data. One big reason for this is the excellent compression that RLE techniques…
