Recommended XFS settings for MarkLogic Server
06 September 2017 08:46 AM
MarkLogic is supported on XFS filesystem. The minimum system requirements can be found here:
The default mount options will generally give good performance, assuming the underlying hardware is capable enough in terms of IO performance and durability of writes, but if you can test your system adequately, you can consider different mount options.
The values provided here are just general recommendations, if you wish to fine tune your storage performance, you need to ensure that you do adequate testing both with MarkLogic and low level tools such as fio:
1. I/O Schedulers
Unless you have a directly connected single HDD or SSD, noop is usually the best choice, see here for more details:
2. XFS Mount options
nobarrier If your disk controller has a battery-backup-unit (BBU) or similar technology to protect the cache contents on power loss, adding the mount option nobarrier for XFS or ext4 can significantly increase throughput. If it doesn't this can lead to to journal data corruption upon power loss.
relatime - The default atime behaviour is relatime, which has almost no overhead compared to noatime but still maintains sane atime values. All Linux filesystems use this as the default now (since around 2.6.30), but XFS has used relatime-like behaviour since 2006, so no-one should really need to ever use noatime on XFS for performance reasons.
attr2 - This options enables an "opportunistic" improvement to be made in the way inline extended attributes are stored on-disk. It's the default and should be kept as such in most scenarios.
inode64 - to sum up this allows xfs to create nodes anywhere and not worry about backwards compatibility, which should result in better scalability. See here for more information: https://access.redhat.com/solutions/67091
sunit=x,swidth=y - XFS allows you to specify RAID settings. This enables the file system to optimize its read and write access for RAID alignment, e.g. by committing data as complete stripe sets for maximum throughput. These RAID optimizations can significantly improve performance, but only if your partition is properly aligned or of you are avoiding misalignment by creating the xfs on a device without partitions.
largeio, swalloc - these are intended to further optimize streaming performance on RAID storage. You need to do your own testing.
isize=512 - XFS allow inlinings of data into inodes to avoid the need for additional blocks and the corresponding expensive extra disk seeks for directories. In order to use this efficiently, the inode size should be increased to 512 bytes or larger.
allocsize=131072k (or larger) - XFS can be tuned to a fixed allocation size, for optimal streaming write throughput. This setting could have a significant impact on the interim space usage in systems with many parallel write and create operations.
As with any advice of this nature, we strongly advise that you always do your own testing to ensure that options you choose are stable and reliable for your workload.