Internal NAS to USB throughput low

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iPeriod
Posts: 10
Joined: 19 Jul 2020, 08:56

Internal NAS to USB throughput low

Post by iPeriod »

Hi,
I am experience lower than expected disk throughput when backing up files from internal NAS to an externally connected JBOD array via USB3.0 (HW & SW details below).
When copying files from a network client onto the NAS via FTP, I consistently see a throughput of 100MB/s. However when backing up from internal NAS using the internal Rsync server I got a consistent throughput of just 50MB/s (~6hr/TB). Installing and using the USB Copy app I saw a slightly higher throughput of just 62MB/s.
I both cases, there was no network NAS access during the NAS backups, just the backup NAS to local USB storage jobs were running.

The hardware should be capable of easily exceeding 100MB/s so why am I see such low throughput figues?

i.

HW
TM F4-210, 2GB
RAID5: 4x X400 4TB
Ext USB 3.0: Icy Box IB-3664SU3, 3x N300 8TB
SW
TOS: 4.1.27-2006291655
USB Copy: 1.5.6
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TMRyan
TerraMaster Team
Posts: 817
Joined: 01 Dec 2020, 11:50

Re: Internal NAS to USB throughput low

Post by TMRyan »

Hi,
How do you check the backup speed when using USB Copy?
How many times has the backup speed shown this way?
It may be slow sometimes due to network problems.
To contact our team, please send email to following addresses, remember to replace (at) with @
Technical team: support(at)terra-master.com (for technical support)
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iPeriod
Posts: 10
Joined: 19 Jul 2020, 08:56

Re: Internal NAS to USB throughput low

Post by iPeriod »

How do you check the backup speed when using USB Copy?
While the copy was progressing I had a SSH connection open into the NAS. During the copying I executed these commands twice after about 5 minute delay:

Code: Select all

date ; df -m /mnt/usb/usbshare2-1
{ delay for ~5 minutes }
date ; df -m /mnt/usb/usbshare2-1
Approximate transfer speed calculated from: transferred bytes / elapsed time

How many times has the backup speed shown this way?
I only performed the transfer once, but it took about 20mins to complete. So an average transfer speed calculated over a 5min period would provide a good estimate of the overall transfer speed.

It may be slow sometimes due to network problems.
The only network activity would be through the SSH connection. The copying was purely internal to the NAS (raid5 --> usb) without accessing to the network stack.

i.
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