Hi,
I'm using debian testing as dom0 with xen 2.0.4 compiled from source.
The machine is named intra2.
The guest OS is SuSE 9.1, named staging, and runs a dataserver (maxdb).
The disk layout is as follows:
disk1 160G
disk2 80G
partition /dev/sda3 5G running dom0
partition /dev/sda5 5G running guest; mounted as: 'phy:sda5,sda5,w';
containing the root installation
partition /dev/md0 software raid0 chunk size 64K build from /dev/sda8
and /dev/sdb1; mounted as 'phy:md0,sda7,w'; containing the database
My impression is that the database performance is less good compaired to
running native on the system, so I started running iostat -xd 5 to see
what is happening on the disks. Clearly, during queries the iowait is
between 99 and 100% for an unusual long time.
I tried to test read performance with with hdparm -t /dev/sda5 in dom0
...
/dev/sda5 DOM0
Timing buffered disk reads: 66 MB in 3.04 seconds = 21.71 MB/sec
Timing buffered disk reads: 50 MB in 3.06 seconds = 16.34 MB/sec
Timing buffered disk reads: 108 MB in 3.02 seconds = 35.76 MB/sec
Timing buffered disk reads: 112 MB in 3.06 seconds = 36.60 MB/sec
Timing buffered disk reads: 166 MB in 3.01 seconds = 55.15 MB/sec
Timing buffered disk reads: 170 MB in 3.00 seconds = 56.67 MB/sec
Timing buffered disk reads: 172 MB in 3.03 seconds = 56.77 MB/sec
Timing buffered disk reads: 170 MB in 3.02 seconds = 56.29 MB/sec
... but ran into a strange phenomenon when the same command was run in
the guest OS ...
/dev/sda5 DOM1
Timing buffered disk reads: 56 MB in 3.05 seconds = 18.36 MB/sec
Timing buffered disk reads: 94 MB in 3.02 seconds = 31.13 MB/sec
Timing buffered disk reads: 138 MB in 3.04 seconds = 45.39 MB/sec
Timing buffered disk reads: 172 MB in 3.00 seconds = 57.33 MB/sec
Timing buffered disk reads: 208 MB in 3.05 seconds = 68.20 MB/sec
Timing buffered disk reads: 246 MB in 3.07 seconds = 80.13 MB/sec
Timing buffered disk reads: 286 MB in 3.13 seconds = 91.37 MB/sec
Timing buffered disk reads: 322 MB in 3.15 seconds = 102.22 MB/sec
Timing buffered disk reads: 358 MB in 3.12 seconds = 114.74 MB/sec
... it's getting faster every time. Why is that?
Not getting answers from hdparm, it tried bonnie++ -d /tmp -r 200 -s 400
-n 0 -b -u root on both dom0 and guest. This is the result for dom0
(intra2) root disk
Version 1.03 ------Sequential Output------
--Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite-
-Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
intra2 400M 26427 98 51944 12 22950 1 17090 58
51638 3 195.4 0
This is the result for guest(staging)
Version 1.01d ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
staging 400M 132810 96 48009 11 53177 5 120590 99 +++++ +++
623.1 0
DOM0,400M,26427 ,98,51944,12,22950 ,1,17090 ,58 ,51638,3 ,195.4,0
Guest ,400M,132810,96,48009 ,11,53177,5 ,120590,99,+++++,+++,623.1,0
For the raid0 device, these are the results:
Version 1.03 ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
intra2 400M 26442 98 71103 16 31414 5 24701 94 69430 6
316.1 1
Version 1.01d ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
staging 400M 133632 96 69970 17 70488 8 120936 99 +++++ +++
619.5 0
DOM0 , 400M,26442 ,98,71103,16,31414,5,24701 ,94,69430,6 ,316.1,1
staging,400M,133632,96,69970,17,70488,8,120936,99,+++++,+++,619.5,0
Based on what I saw with hdparm, can I trust the results from bonnie++?
If somebody knows how to tackle may IO testing problem, please let me
know
Thanx in advance
Cheers,
Filip.
--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
* System Engineer, Verzekeringen NV *
* www.verzekeringen.be *
* Oostkaai 23 B-2170 Merksem *
* 03/6416673 - 0477/340942 *
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
* System Engineer, Verzekeringen NV *
* www.verzekeringen.be *
* Oostkaai 23 B-2170 Merksem *
* 03/6416673 - 0477/340942 *
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
I'm using debian testing as dom0 with xen 2.0.4 compiled from source.
The machine is named intra2.
The guest OS is SuSE 9.1, named staging, and runs a dataserver (maxdb).
The disk layout is as follows:
disk1 160G
disk2 80G
partition /dev/sda3 5G running dom0
partition /dev/sda5 5G running guest; mounted as: 'phy:sda5,sda5,w';
containing the root installation
partition /dev/md0 software raid0 chunk size 64K build from /dev/sda8
and /dev/sdb1; mounted as 'phy:md0,sda7,w'; containing the database
My impression is that the database performance is less good compaired to
running native on the system, so I started running iostat -xd 5 to see
what is happening on the disks. Clearly, during queries the iowait is
between 99 and 100% for an unusual long time.
I tried to test read performance with with hdparm -t /dev/sda5 in dom0
...
/dev/sda5 DOM0
Timing buffered disk reads: 66 MB in 3.04 seconds = 21.71 MB/sec
Timing buffered disk reads: 50 MB in 3.06 seconds = 16.34 MB/sec
Timing buffered disk reads: 108 MB in 3.02 seconds = 35.76 MB/sec
Timing buffered disk reads: 112 MB in 3.06 seconds = 36.60 MB/sec
Timing buffered disk reads: 166 MB in 3.01 seconds = 55.15 MB/sec
Timing buffered disk reads: 170 MB in 3.00 seconds = 56.67 MB/sec
Timing buffered disk reads: 172 MB in 3.03 seconds = 56.77 MB/sec
Timing buffered disk reads: 170 MB in 3.02 seconds = 56.29 MB/sec
... but ran into a strange phenomenon when the same command was run in
the guest OS ...
/dev/sda5 DOM1
Timing buffered disk reads: 56 MB in 3.05 seconds = 18.36 MB/sec
Timing buffered disk reads: 94 MB in 3.02 seconds = 31.13 MB/sec
Timing buffered disk reads: 138 MB in 3.04 seconds = 45.39 MB/sec
Timing buffered disk reads: 172 MB in 3.00 seconds = 57.33 MB/sec
Timing buffered disk reads: 208 MB in 3.05 seconds = 68.20 MB/sec
Timing buffered disk reads: 246 MB in 3.07 seconds = 80.13 MB/sec
Timing buffered disk reads: 286 MB in 3.13 seconds = 91.37 MB/sec
Timing buffered disk reads: 322 MB in 3.15 seconds = 102.22 MB/sec
Timing buffered disk reads: 358 MB in 3.12 seconds = 114.74 MB/sec
... it's getting faster every time. Why is that?
Not getting answers from hdparm, it tried bonnie++ -d /tmp -r 200 -s 400
-n 0 -b -u root on both dom0 and guest. This is the result for dom0
(intra2) root disk
Version 1.03 ------Sequential Output------
--Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite-
-Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
%CP /sec %CP
intra2 400M 26427 98 51944 12 22950 1 17090 58
51638 3 195.4 0
This is the result for guest(staging)
Version 1.01d ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
staging 400M 132810 96 48009 11 53177 5 120590 99 +++++ +++
623.1 0
DOM0,400M,26427 ,98,51944,12,22950 ,1,17090 ,58 ,51638,3 ,195.4,0
Guest ,400M,132810,96,48009 ,11,53177,5 ,120590,99,+++++,+++,623.1,0
For the raid0 device, these are the results:
Version 1.03 ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
intra2 400M 26442 98 71103 16 31414 5 24701 94 69430 6
316.1 1
Version 1.01d ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
staging 400M 133632 96 69970 17 70488 8 120936 99 +++++ +++
619.5 0
DOM0 , 400M,26442 ,98,71103,16,31414,5,24701 ,94,69430,6 ,316.1,1
staging,400M,133632,96,69970,17,70488,8,120936,99,+++++,+++,619.5,0
Based on what I saw with hdparm, can I trust the results from bonnie++?
If somebody knows how to tackle may IO testing problem, please let me
know
Thanx in advance
Cheers,
Filip.
--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
* System Engineer, Verzekeringen NV *
* www.verzekeringen.be *
* Oostkaai 23 B-2170 Merksem *
* 03/6416673 - 0477/340942 *
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
* System Engineer, Verzekeringen NV *
* www.verzekeringen.be *
* Oostkaai 23 B-2170 Merksem *
* 03/6416673 - 0477/340942 *
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*