Mdadm - Known Problems - Increasing RAID5 Performance

Increasing RAID5 Performance

To help RAID5 read/write performance, setting the read-ahead & stripe cache size for the array provides noticeable speed improvements.

Note: This tip assumes sufficient RAM availability to the system. Insufficient RAM can lead to data loss/corruption

echo 16384 > /sys/block/md0/md/stripe_cache_size blockdev --setra 16384 /dev/md0

Write Performance:

dd if=/dev/zero of=/mnt/family/10gb.16384k.stripe.out bs=1M count=10240 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 94.5423 s, 114 MB/s

Read Performance:

dd if=/mnt/family/10gb.16384k.stripe.out of=/dev/null bs=1M 10240+0 records in 10240+0 records out 10737418240 bytes (11 GB) copied, 28.5435 s, 376 MB/s

These changes must be done on any reboot (add to an init script to set on start-up)

Read more about this topic:  Mdadm, Known Problems

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