# when writing to /dev/sdh, root drive gets 250kBps write??

## Oo.et.oO

i first noticed this when backing up my raid setup to an external USB drive.

then i noticed it again yesterday when using a usb 2.0 ide external setup to secure wipe a bunch of old drives.

when writing the data to /dev/sdh (one of my external drives), /dev/sda gets ~250kBps write avg.

same thing happened when rsyncing from /dev/sdb1 to /dev/sdg1 (my two external backup drives)

at least that's what conky says it's getting.  i haven't dug into conky to see if it's maybe just measuring bus activity, but i have two drives monitored on conky and only /dev/sda (the root/home/usr drive) gets this much access.

memory is fine and it's not from the pagefile.

any ideas?

here is the portion of my .conkyrc:

```

${color #98c2c7}/dev/sda read: ${diskio_read sda} write: ${diskio_write sda}  Temp:$color ${hddtemp sda}*C  

${color #78af78}${diskiograph 25,350}$color

```

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## d2_racing

USB 2.0 is pretty slow, so maybe it's normal.

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## LesCoke

If your log files are on /dev/sda, you may be logging errors to /dev/sda when writing to /dev/sdh.

Les

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## eccerr0r

 *? wrote:*   

> USB 2.0 is pretty slow, so maybe it's normal.

 

I've found that USB2.0 reads and writes to an ATA device I can achieve around 20MB/sec give or take, depending on the disk.  What I have not found to be true is that accessing other drives in a properly configured and equipped system that USB accesses slow down the main machine activity much.

How is your USB subsystem interrupt system set up?  Are you using polling?  What USB host controller are you using?

As LesCoke says, see if you are getting warning messages such as usb-storage debugging turned on - does dmesg show any errors/messages during writing?

Do you feel the machine is actually slow during writing to the disk (indicating polling mode) or is just hdd accesses?

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