Hello, first of all, mary christmas for all which read this email to mailinglist.
Since about 14 days, i have a problem with an Xen vServer Host. Hardware Specs: 2x Intel Xeon E5-2620v2 256 GB DDR3 ECC Reg Memory 6x 3 TB WD RE Drives – RAID 10 – HDD Array 2x 256 GB SSDs – RAID 1 – SWAP Drives 2x 600 GB SAS HDDs – RAID 1 – Backup Temp 2x 1 TB SSDs – RAID 1 – xCacheCade LSI MegaRAID 9361-8i MegaRAID Kit LSICVM02 When i boot the Server – OS: Debian 8 – with an Kernel without Xen Hypervisor Support, i get the following Performacne at the RAID 10 HDD Array – the test Script is from: http://blog.tdg5.com/tuning-dd-block-size/ - root@v7:~# ./dd_obs_test.sh datei block size : transfer rate 512 : 293 MB/s 1024 : 469 MB/s 2048 : 603 MB/s 4096 : 812 MB/s 8192 : 866 MB/s 16384 : 845 MB/s 32768 : 875 MB/s 65536 : 929 MB/s 131072 : 923 MB/s 262144 : 898 MB/s 524288 : 956 MB/s 1048576 : 883 MB/s 2097152 : 956 MB/s 4194304 : 925 MB/s 8388608 : 879 MB/s 16777216 : 811 MB/s 33554432 : 826 MB/s 67108864 : 753 MB/s root@v7:/home# time dd if=/dev/zero of=datei bs=1M count=10240 10240+0 Datens㳺e ein 10240+0 Datens㳺e aus 10737418240 Bytes (11 GB) kopiert, 26,3243 s, 408 MB/s real 0m26.327s user 0m0.012s sys 0m17.140s root@v7:/home# time dd if=datei of=/dev/null 20971520+0 Datens㳺e ein 20971520+0 Datens㳺e aus 10737418240 Bytes (11 GB) kopiert, 11,7919 s, 911 MB/s real 0m11.794s user 0m2.612s sys 0m9.176s the read performance from the cache goes up to 1.2 – 1.6 Gb/s When i reboot the Server and boot an kernel with Hypervisor Support, i get the following performance information: root@v7:~# ./dd_obs_test.sh datei block size : transfer rate 512 : 9 MB/s 1024 : 163 MB/s 2048 : 256 MB/s 4096 : 368 MB/s 8192 : 490 MB/s 16384 : 569 MB/s 32768 : 618 MB/s 65536 : 684 MB/s 131072 : 717 MB/s 262144 : 709 MB/s 524288 : 715 MB/s 1048576 : 742 MB/s 2097152 : 728 MB/s 4194304 : 730 MB/s 8388608 : 696 MB/s 16777216 : 655 MB/s 33554432 : 626 MB/s 67108864 : 558 MB/s root@v7:/home# time dd if=/dev/zero of=datei bs=1M count=10240 10240+0 Datensätze ein 10240+0 Datensätze aus 10737418240 Bytes (11 GB) kopiert, 31,6254 s, 340 MB/s real 0m31.712s user 0m0.040s sys 0m15.744s root@v7:/home# time dd if=datei of=/dev/null 20971520+0 Datensätze ein 20971520+0 Datensätze aus 10737418240 Bytes (11 GB) kopiert, 50,6099 s, 212 MB/s I have upgraded Controller Firmware, BIOS, changed mainboard, changed hard drives, changed RAID Controller. I can not find the reason why the performance of the hypervisor kernel is such bad. I have tested Kernel 4.9, Kernel 4.4 and Kernel 3.16.36 default debian. All Versions such the same values. Installed ist he default Hypervisor Version 4.4.1. Has anybody the same problem and could help me to solve it? Yours sincerely Michael Schinzel
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