… this system which had 6 15K SAS hard drives in RAID10. Another indication of bad fragmentation was average IO size seen in…/sec but well below RAID array capacity. To check if file fragmentation is the issue or it is poor or miss configured… about 300MB/sec which confirmed file fragmentation is also the issue. Interesting enough the “cure” for both fragmentation issues is the same – OPTIMIZE…
Comment: Disaster: LVM Performance in Snapshot Mode
February 9, 2009 By 55 Comments
… structured file systems (WAFL, ZFS). With log structured filesystems you get snapshots practically for free but there are other disadvantages like fragmentation… reads/writes done by each thread. My setup was 6 SAS 10K drives with 512MB write-back cache in the controller… block maps of large files can fit into an inode itself if the filesystem is not severely fragmented so mapping your offset…
