I am trying to backup my ReadyNAS Pro to an external USB drive connected to a back USB port, however, the backup speed is incredibly slow. There is approximatly 2 TB of data on the NAS which I am trying to backup, but currently I am averaging transfer speeds of < 2 GB per hour! At this rate the backup will take over a month to complete, which seems wrong. To put this in some more context, I think the USB ports on my NAS are 2.0, which has a transfer rate of 60 MB/s, but I am only getting 0.5 MB/s.
The NAS is running RAIDiator 4.2.31 with fast USB writes enabled, and the external drive is a new Seagate external HD formated as NTFS. I know from reading this forum that NTFS is slower than EXT3, but 0.5 MB/s is way to slow, even for NTFS.
I have tried canceling and restarting the backup, but this has not helped. The backup logs show no errors. Does anyone know where to look for what could be causing this issue or how to resolve it?
Hi @David_H, it could be related to the NTFS cluster size set to 512Bytes for whatever reason.
Under windows you can find out the current cluster size by executing as admin eg using powershell
fsutil fsinfo ntfsinfo X:
When formatting an NTFS hardisk you can choose how big the clusters should be to hold your data. The cluster size can range from 512 Bytes to 64 KBytes.
Choosing the lowest you will save maximum amount of diskspace possible, which unfortunately will result in lots of administrative overhead for large files (allocating all necessary clusters and filling them). For example a 200MB file will occupy roughly 400,000 clusters, which need to be allocated and filled with data in this case.
Choosing the highest you will waste a lot of diskspace, but adminstrative overhead is low and your drive will be faster and not that fragmented. For example a file of 10 Bytes will unfortunately occupy 64 KBytes, though.
In essence, you need to find out the optimum cluster size for your situation. Dealing with media files only (movies, fotos, music) it should be beneficial to choose a higher cluster size eg 32KBytes. With lots of very, very small files you might want choose a cluster size closer to 512Bytes (4 KBytes is the default cluster size formatting drive with Windows).
Nevertheless, there is a conflict between speed on the one hand and using space to the maximum extend on the other hand.
I haven't benchmarked this myself, but I believe the normal backup speed for NTFS on the Pro-6 would be around 10 MB/s. NTFS cluster size could be part of the issue, but I don't think that would account for all of it. It should be 4 KB.
Another option on formatting is to switch to EXT. But if you do that, I strongly recommend getting EXT drivers on your PC, so you can read the backup on another device. Paragon has an inexpensive package that supports it: https://www.paragon-software.com/us/home/linuxfs-windows/
If you have another (perhaps older) USB drive, you could try a test with that connected to the NAS, and see if you get better speeds.
The Pro 6 only has USB 2.0, so you will get faster backup speeds over gigabit ethernet. Current disk drivers in Windows (or Mac) might also give you better performance with SMR. The disk drivers in your Pro pre-date that technology.
Thanks for the suggestions. I checked and the cluster size is set to 4 KB. The SMR idea is a possibility, I think it is an SMR drive. Unfortunately I don't have a standard drive around to test with right now.
I feel like the speeds I'm getting are still low for writing to a previously empty SMR drive, since it would not have to overwrite previous tracks, but I don't really know the details of how this operates.
I guess I'll have to find a different drive to test with if I want to narrow down the issue further.
I feel like the speeds I'm getting are still low for writing to a previously empty SMR drive, since it would not have to overwrite previous tracks, but I don't really know the details of how this operates.
I don't think the disk knows that it doesn't have to overwrite, since it isn't file-system aware. The only mechanism would be if it is aware of never-written tracks. That seems unlikely, though I guess it is possible.
Back when these drives were first introduced, there were driver modifications made in linux to improve their performance. But the pro-6 was already near end-of-life when that happened, and they weren't back-ported to it. That's why I am thinking that you might get better speed if you back up over the network (connecting the drive to a PC).
