Does MDADM still have the bug of RAID5 ext4 being capped at 350MiB/s?
by road hazard from LinuxQuestions.org on (#4WXN0)
I know that the following thread is roughly 10 years old but:
http://lkml.iu.edu/hypermail/linux/k...2.3/01654.html
... I'm using that exact setup. When I copy a 50 gig file from my SSD to my RAID 6 XFS array, it maintains a steady xfer rate of about 560MB/s. When I copy the same file to my RAID 5 ext4 array, it starts off around 500MB/s then quickly falls to 400MB/s......15 second pause of no disk activity then the xfer resumes at around 150MB/s......another long pause then speeds slowly climb to around 250MB/s then 300MB/s and don't get much faster than that.
The RAID 6 array is a bunch of 4TB NAS drives and the 8TB array is a few WD Red NAS drives. I think tomorrow morning, I'm going to trash my RAID 5 array and format it to XFS then copy 35TB of data back. That will be fun! :)
fstab for my RAID 5 array
Code:/dev/md127 /mnt/backup ext4 defaults,init_itable=0,nofail,discard,relatime,barrier=0,commit=60,data=writeback 0 0
http://lkml.iu.edu/hypermail/linux/k...2.3/01654.html
... I'm using that exact setup. When I copy a 50 gig file from my SSD to my RAID 6 XFS array, it maintains a steady xfer rate of about 560MB/s. When I copy the same file to my RAID 5 ext4 array, it starts off around 500MB/s then quickly falls to 400MB/s......15 second pause of no disk activity then the xfer resumes at around 150MB/s......another long pause then speeds slowly climb to around 250MB/s then 300MB/s and don't get much faster than that.
The RAID 6 array is a bunch of 4TB NAS drives and the 8TB array is a few WD Red NAS drives. I think tomorrow morning, I'm going to trash my RAID 5 array and format it to XFS then copy 35TB of data back. That will be fun! :)
fstab for my RAID 5 array
Code:/dev/md127 /mnt/backup ext4 defaults,init_itable=0,nofail,discard,relatime,barrier=0,commit=60,data=writeback 0 0