Why VMware Virtual disk so slow (da0: 3.300MB/s transfers) ?

[Dongsheng Song]

On Sat, Aug 24, 2013 at 11:52 AM, Sascha Wildner <saw at online.de> wrote:
> On Mon, 19 Aug 2013 09:55:12 +0200, Dongsheng Song
> <dongsheng.song at gmail.com> wrote:
>
>> Hi,
>>
>> When I running DragonFlyBSD under VMware ESXi 5.1, with the following
>> setting:
>>
>> CPUs: 8
>> Memory: 4096 MB
>> SCSI controller: LSI Logic Paraller
>> SCSI disk size: 64G
>>
>> I found this VM is very very slowly, then I check the dmesg output,
>> I'm very surprised:
>>
>> da0: 3.300MB/s transfers
>
>
> Could you try with this patch please?
>
> http://leaf.dragonflybsd.org/~swildner/cam_probe.diff
>
> Sascha

No IO speed difference (0.200 ~ 0.400 MB/s).

The dmesg output just add new line:
da0: Command Queueing Enabled

# dmesg  | grep -E "da0: | mpt0: "
da0 at mpt0 bus 0 target 0 lun 0
da0: <VMware Virtual disk 1.0> Fixed Direct Access SCSI-2 device
da0: 3.300MB/s transfers
da0: Command Queueing Enabled
da0: 65536MB (134217728 512 byte sectors: 255H 63S/T 8354C)