Date: Tue, 2 Sep 2014 19:25:11 +0200 From: =?UTF-8?B?Um9nZXIgUGF1IE1vbm7DqQ==?= <roger.pau@citrix.com> To: Marko Lerota <mlerota@pdsvelebit.hr> Cc: FreeBSD XEN <freebsd-xen@freebsd.org> Subject: Re: Poor disk IO on Xenserver 6.2 Message-ID: <5405FD77.2000102@citrix.com> In-Reply-To: <86tx4un8bd.fsf@cosmos.claresco.hr> References: <86lhq7odub.fsf@arch.perpetuum.hr> <5400B39E.3090904@citrix.com> <86tx4un8bd.fsf@cosmos.claresco.hr>
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El 30/08/14 a les 2.13, Marko Lerota ha escrit: > Roger Pau Monné <roger.pau@citrix.com> writes: > >> El 29/08/14 a les 11.16, Marko Lerota ha escrit: >>> I have installed FreeBSD 10 release, stable and current on >>> Xenserver 6.2 with latest patches. All of them have poor disk >>> write speed. Performance from 12MBps - 25MBps. I tried it on >>> other servers but the performance is the same. Latest Debian >>> stable on the same machine have 300MBps disk speed. Am I missing >>> something after installation or this is the default speed? >>> >> >> I've certainly seen higher speeds, around 25-35MB/s on my box, which is >> the same speed I can get with a Linux guest. Could you describe how you >> are running your tests? > > You copy some *.tar.gz or *.iso file that have 600 MB. If it finish > in 2-3 seconds than it's fine. If it runs 40 seconds than it's very, > very bad. You can see current disk speed with 'iostat 1'. Today I have > installed FreeBSD 10-Release on KVM and it runs smooth. Files are > copied at 150-300MB per second. That's how it should be. Suppose that > you need to copy or sync files with another disk/partition very often. > It would be very painful and long process. There is definitely something > wrong here. I've just did some _very_ simple disk benchmarks using fio on both Linux and FreeBSD using a 1GB ramdisk as the backend: 'phy:/dev/ram0,hdd,w' This was added to the guests, both have 1GB of RAM and 8vcpus. Then I've used the following fio workload: [global] rw=write # or read for the read tests size=900m bs=32k direct=1 # tested both 0 and 1 [job1] FreeBSD was able to deliver >30000iops in all cases, and the throughput was around 1000MB/s for all test cases also. On the other hand, Linux was only able to deliver around 10000iops, with a throughput of ~400MB/s. This was tested using xen-unstable and a Linux v3.15 Dom0. Could you try to run this benchmark on both your FreeBSD and Linux guests? Please make sure guests are set to use the same amount of RAM/CPUs. Roger.
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