QNap NAS is slow to read and fast to write

First, search your NAS using a terminal window (possibly via ssh if it is not possible to open a terminal via its web interface, you may then have to activate ‘ssh’ support first) and using the ‘dmesg’ command (eg sudo /root) If it writes something worrying about a problem on some disk with timeout, rewriting data and giving I/O error etc.

The mdadm-RAID or perhaps LVM-RAID that Qsnap uses can be very slow if you have a disk that makes half the noise when reading, but not so much that the disk is kicked out by very long timeouts. I had a WD Green HD drive that did exactly that and it wasn’t so serious that it kicked out and none of the issues registered in SMART for the drive and so it went under the system’s radar.

Is it possible to install the program “atop” using “apt” on a NAS and run it via ssh on a very wide terminal window and using the command “atop -fF 1” as sudo/root you can proceed with a one second update, for example. If any disk constantly seems “busy”, has long command queues and long response times when writing or downloading large files – likewise if there seems to be a bottleneck in the network hardware or if you see if the CPUs are rushing under load (e.g. Example: If you are working with encrypted transport, which can be too heavy for a NAS unless HW support for encryption is used but is emulated by the software instead [vilket är tyvärr inte allt för sällan för att man inte har rätt libbar för att använda ARM/Intels HW-kryptering] ), further search in “irq”, “waiting” and “idle”

One method you can try is to try downloading files via NFS instead of SMB and see if there is a significant difference in download speed, if so, you may need to review your SMB server configuration. – This stuff about downloading files using NFS should be done on Linux, as making NFS work under Windows can be difficult and you have to search for software packages etc. – It’s also a good idea to try downloading files via SMB via Linux instead of windows if it’s slow too seeing that windows is not the cause of the drama for example. ‘defender’ (MS’s AV software) which chews the file as it downloads.

Defender is a typical AV program that only chews up files received over the network before they reach the disk but not what is sent away.