We use a simple backup system at work: Every day we connect an external USB harddisk to our Ubuntu Linux server, which then calls a backup script (cronjob) at night to perform all the backup. Next day we disconnect the USB harddisk, and plug in another one. So we always have two harddisks with backups.
This has worked fine for over a decade with various harddisks from different manufacturers.
But recently we bought a Toshiba Canvio 2TB harddisk, and ever since I've struggled with insanely slow speeds. (Like 1,5 mbps). When searching for this problem I find a ton of posts on various forums from people struggling with the same thing. And there are many suggestions about what to try - but none of them makes any difference whatsoever.
This Toshiba Harddisk takes 66 minutes to copy 10 gb from a folder. Our other harddisk does the same job in just a single minute. But when connected to a Windows PC, the Toshiba harddisk seems to be working fine with fast speeds. So it's a Linux thing apparently.
The backup script uses wget to get files from FTP sites, from both LAN and WAN. A full backup takes about 5 hours (on a good harddisk).
Here is a list of things I've tried so far:
- I checked and confirmed that the cable is actually connected to a USB3.0 port of course (which shouldn't matter though since the other harddisk using the same port and the same cable works just fine and fast)
- I tried another Toshiba Canvio harddisk, different sub-model - was also incredibly slow.
- I tried setting /proc/sys/vm/dirty_bytes and dirty_background_bytes
- I tried setting /proc/sys/vm/swappiness to 1
- I've tried setting --limit-rate on wget to different values, like 20m and 50m
- I've tried formatting to different filesystems, like ext4
- I also tried both gpt and msdos - not that it should matter
Those are all suggestions I've found on various sites during the past week, but none of them makes any difference in my case whatsoever.
At this point I'm extremely curious to learn why this is happening. What is it with these Toshiba harddisks that Linux doesn't like? In other words: What should I look for when buying harddisks to avoid this in the future?