Speed of the NAS 326

MGabor Posts: 1
edited October 2019 in Personal Cloud Storage
Dear All, Yesterday I bought a NAS 326. I have installed 2x2TB WD HDD. I use in RAID 1. The speed of the copying from USB3 to NAS HDD and moving NAS HDD to NAS HDD is very slow, 500-650 KB/s. Is it normal?


All Replies

  • Mijzelf
    Mijzelf Posts: 1,721  Guru Member
    Is it normal?
    Depends on the nature of the data, and your network. The NAS should be able to do about 100MB/sec in a single direction on cabled gigabit ethernet. For big files.
    When copying a large amount of small files the speed decreases dramatically, mainly because of the terrible seek time of a hard disk.

    (A normal harddisk can do about 150MB/sec, when it's transferring a contiguous amount of diskspace. But when the heads have to be move to another part of the disk, it typically takes 20msec. If you write files of 1 bytes each, the disk has to search for their location, and then write 1 byte, which it can do 1000/20 = 50 time per second. The theoretical 150MB/sec is downgraded to 50bytes/sec. Actually worse, as we are omitting the administration on disk now. (This is the reason an SSD is that fast. The seektime is dramatically shorter, as no mechanics are involved))
    This becomes even worse if you are moving from one share to another. You PC cannot know the shares are actually on the same disk. So it will download the files, and upload them again. The disk has to seek for the files to provide them, and then seek again to put them on a new place.
    For this reason there is a 'lower-level' share with a name as 'Volume1' or something like that. You can enable it in the shares menu, and only admin can access it. The 'real' shares are subdirectories in this share, and so the move of a file from one subdirectory to another is only administrative, and fast.

    Another problem can be the network. If you are on wireless, you can't expect it to work as good as cable. Cable is full duplex, data can run in both directions simultaneous, but wifi is monodirectional, and shared. So devices have to wait for each other to say something.

    Did you connect that USB3 disk to the NAS? You will get a higher throughput if you connect it to your PC. Instead of down- and uploading you only have to upload.