# vmware ESXi slow disk speed



## Dara (Jun 14, 2010)

Hi, just tough that i might share some nice info.. 

I have several vmware ESXi (3.5x and 4.x) servers and alot of FreeBSD VM:s (7.x and 8.0) and have had allot of problems with slow disk speed.. 

And i just updated some of the ESXi:s with the latest updates from vmware (now version 4.0.0 build 261974) and the disk problem seems to have gone away..

I have search for answers to this for quite a while and was concerned that i would have to change to linux or even worse Windows..  so for me at least this was good news.

/Daniel


----------



## vigolcom (Dec 25, 2010)

Outdated threads, but could useful for someone!
tips:
1- Using non-growable or preallocated VMDK disks.
2- Remove all snapshots in the guest operating system or store performance-sensitive data on an independent virtual disk
3- Install the host operating system onto a separate hard disk than the virtual machines
4- Store the paging file or swap partition on a different drive than the host operating system.
5- Run disk defragmentation software on the host and in the guest operating system.
6- Implementing partitions inside the guest operating system or host can improve performance by creating fragmentation boundaries and can reduce further fragmentation.
7- Certain RAID configurations can impact read or write performance positively and negatively.
8- Disk encryption can reduce disk performance.
9- Often disk problems such as bad sectors or failing controllers can impact performance because I/O and bad cluster auto-recovery can cause sudden interruptions in I/O operations to the device.
10- In general, hardware RAID and independent disk controllers perform better than software RAID and integrated disk controllers.
11- Adding the following settings to a virtual machine can reduce the I/O load on the hard disk, however these adjustments require additional memory on the host.
_Open the .vmx file for the affected virtual machine while it is powered off. Add the following lines to the file using a text editor.
Note: If you are using VMware Server, you may need to restart the VMware Authorization Service (vmware-authd) for changes to take effect. _

```
MemTrimRate = "0"
mainMem.useNamedFile= "FALSE"
sched.mem.pshare.enable = "FALSE"
prefvmx.useRecommendedLockedMemSize = "TRUE"
```


----------

