N36L slow file transfers

[etsi]

Hello, I'm trying unraid and I'm interested to buy a license but I have some problems with N36L. I have the same problem like some other people have already posted in the past; file transfers starts at 90-100mbps and drops to less than 30mbps. I have patched the bios, set write cache to yes and a lot of other advices I have read.  Nothing works. The disk I have are slow I have tested them and I can write/read at 80-90mb/sec for the greens and 140mb/sec for the samsung.

 

SAMSUNG_HD103SJ - 1 TB (parity)

WDC_WD10EADS-00L5B1 - 1 TB

WDC_WD10EADS-00M2B0 - 1 TB

 

I had no problem with file transfers using the same disks and raid5 on another system. Is there a way to make it faster or the combination of slow cpu/hard disks isn't enough for unraid?

 

Thanks

 

 

[JorgeB]

Due to the way unRAID works and because you're using older and slower disks, writes at 30MB/s sounds about right using the default write mode, you can dramatically increased them by turning turbo write on.

[etsi]

Thanks for the advice, I tried reconstruct write mode and it's faster but not like raid5 but much better than before. If I add a small ssd as a cache disk I will be able to hit 90-100mb/sec file transfers?

[JorgeB]

Thanks for the advice, I tried reconstruct write mode and it's faster but not like raid5 but much better than before. If I add a small ssd as a cache disk I will be able to hit 90-100mb/sec file transfers?

 

Yes, using modern disks with turbo write should also max a gigabit connection.

 

unRAID will never have similar speeds to RAID5 because data on disks is not stripped, however if more than one disk fails data on all others can be read, unlike RAID5.

[etsi]

root@zeus:/mnt# mdcmd set md_write_method 1
root@zeus:/mnt# dd if=/dev/zero bs=10M of=/mnt/disk1/test.tmp count=256 conv=fdatasync
256+0 records in
256+0 records out
2684354560 bytes (2.7 GB, 2.5 GiB) copied, 32.6126 s, 82.3 MB/s
root@zeus:/mnt# mdcmd set md_write_method 0
root@zeus:/mnt# dd if=/dev/zero bs=10M of=/mnt/disk1/test.tmp count=256 conv=fdatasync
256+0 records in
256+0 records out
2684354560 bytes (2.7 GB, 2.5 GiB) copied, 75.4216 s, 35.6 MB/s
root@zeus:/mnt# mdcmd set md_write_method 1
root@zeus:/mnt# dd if=/dev/zero bs=10M of=/mnt/disk1/test.tmp count=256 conv=fdatasync
256+0 records in
256+0 records out
2684354560 bytes (2.7 GB, 2.5 GiB) copied, 31.8974 s, 84.2 MB/s
root@zeus:/mnt# mdcmd set md_write_method 0
root@zeus:/mnt# dd if=/dev/zero bs=10M of=/mnt/disk1/test.tmp count=256 conv=fdatasync
256+0 records in
256+0 records out
2684354560 bytes (2.7 GB, 2.5 GiB) copied, 75.3527 s, 35.6 MB/s