write speed to usb stick slows with time

Pedroski · 05-01-2018, 06:00 AM

Bought a new 32GB usb 3.0 memory stick. If I copy a lot of stuff to it, it starts off fast 5+MB/s, but slows eventually to KBs.

I also noted this when writing to my external hd sometimes.

Is there a logical reason for this?

syg00 · 05-01-2018, 07:28 AM

Read this.

Logical ?. Hmmm ....

ondoho · 05-01-2018, 09:19 AM

that's a nice article (i remember reading it before), but:

Quote:

This kind of change could conceivably be merged for 3.13; fancier solutions, obviously, will take longer.

shouldn't we be way beyond that point by now, even for conservative distros?

Quote:

Originally Posted by Pedroski

Bought a new 32GB usb 3.0 memory stick. If I copy a lot of stuff to it, it starts off fast 5+MB/s, but slows eventually to KBs.

how do you copy? command line, or gui filemanager?
i noticed that some filemanagers aren't good at this, and a command line 'cp' is faster.

how do you measure the speeds?

syg00 · 05-01-2018, 06:09 PM

Sorry, it really answers another q, not the one asked.
And no, the defaults haven't changed as at 4.15.

As for this, in the light of morning, I'd be guessing USB specific buffer issue.

Pedroski · 05-01-2018, 09:06 PM

I just right click a folder, then click 'copy to', not being an expert in these matters.

Just tried again: my Music folder is 12.5 GB

Starts out reasonably fast, but within a couple of minutes, it says: 2 hour 25 mins to complete.

I thought usb 3.0 should copy at 27 MB/s

Is there anything I can do about this?? Otherwise I will return the usb stick.

Pedroski · 05-02-2018, 07:29 PM

I will send this Kingston 32GB usb 3.0 stick back, so I thought I better delete all the files.

Have a look at this screenshot!

syg00 · 05-02-2018, 07:35 PM

Just mkfs over the top - NTFS zeroes by default.

Pedroski · 05-03-2018, 12:35 AM

Could that be the problem, the usb is formatted msdos?

ondoho · 05-03-2018, 11:50 AM

45000 files? that's a lot.
i repeat, a simple 'rm -r' would have been much faster (but still noticeable witht hat many files)

and "msdos" is not a filesystem; how exactly is the drive formatted?
could well have sth to do with it.

Code:

sudo fdisk -l /dev/sdX

(replace X with the device letter)

_roman_ · 05-03-2018, 01:02 PM

Quote:

Originally Posted by Pedroski

Bought a new 32GB usb 3.0 memory stick. If I copy a lot of stuff to it, it starts off fast 5+MB/s, but slows eventually to KBs.

I also noted this when writing to my external hd sometimes.

Is there a logical reason for this?

which kind of stick.

some cheap brands are very slow

and having many files, which is the case in your case, also slows it down

--

just make one big archive and copy the archive. than you will see what the best speed of your hardware is.

Shadow_7 · 05-03-2018, 03:28 PM

Some sticks slow down a lot when you go > 50% of the capacity. Some sticks are just slow.

michaelk · 05-03-2018, 08:18 PM

True, msdos is not a filesystem but most of the utilities to format a FAT filesystem have dos in the name i.e. mkdosfs = mkfs.msdos = mkfs.vfat.

There could be multiple reasons why file transfer is slow but FAT32 is inefficient when writing a large number of files. FAT32 also becomes inefficient when the filesystem is large which one of the reasons why Microsoft artificially created the upper limit at 32GB in its formatting utilities.

Here is one site that shows the numbers.

https://www.flexense.com/fat32_exfat...omparison.html

Pedroski · 05-04-2018, 01:45 AM

Well, I sent it back, complained. See what they say!

The 16GB Kingston usb 3.0 works fine!

Pedroski · 05-04-2018, 09:45 PM

They gave me a new one:

pedro@pedro-school2:~$ sudo fdisk -l /dev/sdb
[sudo] password for pedro:
Disk /dev/sdb: 28.8 GiB, 30943995904 bytes, 60437492 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x596f7a2f

Device Boot Start End Sectors Size Id Type
/dev/sdb1 * 63 60435647 60435585 28.8G b W95 FAT32
pedro@pedro-school2:~$

Hope it works better! No time to try now.