Is there any lower limit on Disk Image IO bandwidth

Discussions about using Linux guests in VirtualBox.

Is there any lower limit on Disk Image IO bandwidth

Postby harishpathangay » 19. Jul 2019, 14:47

Hi,
I am using VBOX 6.0.8. r130520 with Ubuntu Mate Linux Guest, Host Win 10.
Trying to use IO bandwidth on Virtual Hard Disk Image of 2GB capacity, formatted with xfs file system.
created bandwidth group "IOB" with io speed 1KB/sec. Associated the 2GB drive with IOB bandwidth group.
But I am getting 1.5MB/sec when I copy a 1.2GB file as data transfer rate, iostat output displays kb_written/sec as 1.5MB/sec
Is there are any lower limit on IO bandwidth?

please find attached the vbox xml config file.

thanks,
harish pathangay
Attachments
Matay.xml
(7.16 KiB) Downloaded 8 times
harishpathangay
 
Posts: 26
Joined: 13. Mar 2017, 12:54

Re: Is there any lower limit on Disk Image IO bandwidth

Postby mpack » 19. Jul 2019, 16:24

The manual says that this feature only applies to asynchronous I/O, so what happens if you enable the "Use host I/O cache" option on the controller?
mpack
Site Moderator
 
Posts: 29817
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Is there any lower limit on Disk Image IO bandwidth

Postby harishpathangay » 19. Jul 2019, 18:20

hi,
host I/o cache is not enabled. did not test it.
the command I am using for test is
dd if=/dev/zero of=/media/iob/dblog/laptop.bin bs=512 oflag=direct
the above command fills up entire disk of 2GB.at the rate 1.4mbps.
I understand I am performing direct io on the command, but not sure whether it is asynchronous.

in other words, I just want to go to the lowest io rate as possible in io bandwidth feature of virtual box.
not sure what is that minimum rate of io.

thanks,
harish p
harishpathangay
 
Posts: 26
Joined: 13. Mar 2017, 12:54


Return to Linux Guests

Who is online

Users browsing this forum: No registered users and 7 guests