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View Full Version : 10MB/s is normal tap:aio:file.raw?



Flako000
04-Sep-2014, 23:51
Hi there
I am analyzing disk performance. I'm testing raw (tap: aio) and lvm (phy :).
The tests I'm doing on a SLES11SP3, cpu I7, 4GBRam, disk SATAII 7200rpm.

With phy: lvm achievement 70-80MB / s (an acceptable value)
With tap: aio: file.raw achievement 5-9MB / s, which is very low ...

10MB/s is what you should expect access to a tap: aio: file.raw? or I have something misconfigured?

Also file.qcow probe, such as changing the parameters of the scheduler to noop in the domU, but the performance is kept low.
It is normal file.raw those values​​?


my cfg is:

name = "satotestx"
maxmem = 1024
memory = 1024
vcpus = 4
bootloader="/usr/bin/pygrub"
boot = "dc"
pae = 0
acpi = 1
apic = 1
hap = 1
viridian = 0
hpet = 0
rtc_timeoffset = 0
localtime = 0
on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "destroy"
sdl = 0
vnc = 1
vncunused = 1
keymap = "en-us"
disk = [
"tap:aio:/mnt/util/Descargas/SystemRescueCdOnSuse-0.0.1/SystemRescueCdOnSuse.x86_64-0.0.1.raw,xvda,w"
,"tap:aio:/mnt/xendomain/satotest/disco1.raw,xvdb,w"
,"phy:/dev/globalNew/satotest,xvdc,w"
]
parallel = "none"
serial = "pty"
usb =

Thanks for reading so far down ...

Flako000
22-Oct-2014, 23:53
Well after testing,
For it to work properly Blktap2 you use "tap2:aio:file.raw ', this is achieved with 70-80Mb / s (acceptable values ​​in a SATAII disk)

jmozdzen
23-Oct-2014, 11:38
Hi Flako000,

thank you for reporting back your findings - I'm sure others will find this helpful!

Regards,
Jens