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Separate ZFS Intent Logs?

April 26, 2017intent logs separate ZFs

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Separate ZFS Intent Logs?

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Based on http://blogs.sun.com/perrin/entry/slog_blog_or_blogging_on , I ran some tests comparing separate intent logs on either disk or SSD (slogs) vs the default chained logs (clogs). For the large block sequential workload, “tuning” the configuration be adding separate ZFS Intent Logs actually slowed the system down slightly. Results: With tuning, the Sun Storage J4400 Arrays via NFS achieved write throughput of 532 MB/Sec and read throughput of 780 MB/sec for a single ‘dd’ stream. $ /bin/time dd if=/dev/zero of=/mnt/jbod/test-80g bs=2048k count=40960; umount /mnt/jbod; mount /mnt/jbod; /bin/time dd if=/mnt/jbod/test-80g of=/dev/null bs=2048k 40960+0 records in 40960+0 records out real 2:33.7 user 0.1 sys 1:30.9 40960+0 records in 40960+0 records out real 1:44.9 user 0.1 sys 1:04.0 With tuning, the Sun Storage F5100 Flash Array via NFS achieved write throughput of 496 MB/Sec and read throughput of 832 MB/sec for a single ‘dd’ stream. $ /bin/time dd if=/dev/zero of=/mnt/lf/test-80g bs