Hello all, best wishes for this new year ,
Stop me if I'm wrong, I've checked through the posts and it seems to be relatively well-admitted that Windows Guest on linux host suffers from disk IO performance.
But I think I've crossed the line of 'poor' performance, so I hope there may be something to d. My config is the following:
HOST is linux RedHat 2.6.9-34.ELsmp, two SATA2 disks in RAID 1. Whenever idle, the hdparm shows a reasonnable 70 - 80 Mb/sec .
GUEST is Windows 5.2 (Win2003 SP2). When copying a 1,5 Gb file within the GUEST, the figures are the following:
HDPARM excerpt taken at 20 seconds interval:
Timing buffered disk reads: 14 MB in 3.17 seconds = 4.42 MB/sec
Timing buffered disk reads: 14 MB in 3.23 seconds = 4.34 MB/sec
Timing buffered disk reads: 8 MB in 3.04 seconds = 2.63 MB/sec
IOSTAT excerpt with 10 seconds interval:
extended device statistics
device mgr/s mgw/s r/s w/s kr/s kw/s size queue wait svc_t %b
sda 0 217 13.0 61.0 110.0 1112.5 16.5 2.1 27.8 13.2 98
extended device statistics
device mgr/s mgw/s r/s w/s kr/s kw/s size queue wait svc_t %b
sda 0 241 1.9 65.2 10.0 1229.2 18.5 3.5 51.9 14.3 96
extended device statistics
device mgr/s mgw/s r/s w/s kr/s kw/s size queue wait svc_t %b
sda 0 232 0.5 62.1 2.0 1175.9 18.8 1.8 28.7 15.6 98
The vmx and vmware.log are attached to this post. The main best practice seems to move the vmem file in a memory mapped section (/tmp in my case). Here are a couple of recommandations I've seen on the web and that I've applied to my vm, but without fully understanding them I admit:
MemTrimRate=0
sched.mem.pshare.enable
= "FALSE"
mainMem.useNamedFile
= "FALSE"
mem.ShareScanTotal=0
mem.ShareScanVM=0
mem.ShareScanThreshold=4096
sched.mem.maxmemctl=0
MemAllowAutoScaleDown
= "FALSE"
I have also looked for a way to disable the verbose mode in the vmware.log that writes a line everytime a batch is sent to the vmdk such as:
Jan 09 12:04:37.423: vmx| scsi0:2: Command WRITE(10) took 2.219 seconds (ok)
I'm wondering if anytime a WRITE is passed to the VM a line is written in the log file is a good thing for disk IO.
Well, don't hesitate to burn me if my questions are that dum, I'm not (yet) that familiar with vmware.
Many thanks for your advice,
Flambant-Neuf