FSBlockSize, Metadata Disk Size, and JournalSize Settings

The FsBlockSize (FSB), metadata disk size, and JournalSize settings all work together.

Beginning with StorNext 5, all file systems use a File System Block Size (FsBlockSize [FSB]) of 4KB. This is the optimal value and is no longer tunable. Any file systems created with versions prior to StorNext 5 will be automatically converted to use 4KB the first time the file system is started with StorNext 5. While internally file Systems which have been upgraded from StorNext 4.x will use a 4KB block size, StorNext tools will continue to display the original FsBlockSize values. This is done to ensure that StorNext 5 can continue to support prior versions of StorNext clients.

Metadata Disk Size Setting

When sizing volumes for metadata, provision an additional 2GB of metadata per million files and directories in the file system.

JournalSize Setting

Beginning with StorNext 5, the recommended setting for JournalSize is 64Mbytes.

Increasing the JournalSize beyond 64Mbytes may be beneficial for workloads where many large size directories are being created, or removed at the same time. For example, workloads dealing with 100 thousand files in a directory and several directories at once will see improved throughput with a larger journal.

The downside of a larger journal size is potentially longer FSM startup and failover times.

Using a value less than 64Mbytes may improve failover time but reduce file system performance. Values less than 16Mbytes are not recommended.

Note: Journal replay has been optimized with StorNext 5 so a 64Mbytes journal will often replay significantly faster with StorNext 5 than a 16Mbytes journal did with prior releases.

A file system created with a pre-5 version of StorNext may have been configured with a small JournalSize. This is true for file systems created on Windows MDCs where the old default size of the journal was 4Mbytes. Journals of this size will continue to function with StorNext 5, but will experience a performance benefit if the size is increased to 64Mbytes. This can be adjusted using the cvupdatefs utility. For more information, see the command cvupdatefs in the StorNext MAN Pages Reference Guide.

If a file system previously had been configured with a JournalSize larger than 64Mbytes, there is no reason to reduce it to 64Mbytes when upgrading to StorNext 5.

Example (Linux)

<config configVersion="0" name="example" fsBlockSize="4096" journalSize="67108864">

Example (Windows)

JournalSize 64M