VMware Cloud Community
sunnythao201420
Contributor
Contributor
Jump to solution

How much of datastore should be left for the host its own to run

Hi all,

I have EXSI 5.5 host installed recently. I am going to create a new VM machine on that host but the datastore on that host is about 2TB and I want to set 1.8TB for my VM machine so I only have 0.2 TB left. The question is that with 0.2 TB left there, whether it is enough for the host to run its own code and data structures? How to determine how many should be left?. The same question for memory and CPU usage.

Could you please help on this?

Thanks a lot.

Regards,

Thao

1 Solution

Accepted Solutions
krish290785
Enthusiast
Enthusiast
Jump to solution

ESXi is pretty much Ligh weight. During the Installation, the ESXi would create partitions automatically. The Patitions to hold bootbank (main code), altbootbank, 4 Gigs vfat, store partition for Tools and etc., This would be enough for the ESXi to run and wouldn't require anything else. A total of around 5 G of the space is used and the rest would be left out for you to create datastores to store virtual machines.

From the left out space, Ensure that you have left at least 20 to 30 GB per VM separately to run snapshots during your patch/maintenance cycles.

-Bala Krishna Gali If the above info is useful, please mark answer as correct or helpful.

View solution in original post

Reply
0 Kudos
7 Replies
KSethi
Enthusiast
Enthusiast
Jump to solution

Hello Thao,

This can help in the above case. http://www.simongreaves.co.uk/vmfs-datastore-free-space/

Rgds

Kanishk

Reply
0 Kudos
sunnythao201420
Contributor
Contributor
Jump to solution

Hi Kanishk,

Thank you very much for your replied.

Can I have a question please? Why we have two *1.1 in the formula you know?

Regards,

Thao

Reply
0 Kudos
KSethi
Enthusiast
Enthusiast
Jump to solution

Hello Thao,

The * 1.1 is to add 10% to the overall solution, to allow for snapshots.


Kindly mark it as helpful/correct answer if this answer your query.


Rgds

Kanishk

Reply
0 Kudos
sunnythao201420
Contributor
Contributor
Jump to solution

Thanks for your prompt answer.

I just want to make it clear on my understanding. Can you please help to correct if I am wrong. Surely that when I get everything clear, I will mark the question as answered.

Example: I have a ESXi host have datastore 3.08 TB = 3153 GB. There is no VM machine created yet. Now, I want to create a new VM machine on that host with total hard disk about 2024 GB and RAM = 32 GB

According to the formula I would have: (2024 + 32*1.1)*1.1 + 12 = 2277 GB.

So the question is that with the amount of datastore left of 3153 - 2277 = 876 GB, is 876 GB enough for my ESXi to run its own code and structure?

My understanding from the case: VMFS Datastore Free Space Calculations | Simon Greaveshttp://www.simongreaves.co.uk/vmfs-datastore-free-space/ to give you how to calculate the physical disk space in total before you can start creating VM machines. It seemed to be a bit different from my question above.

Please advise.

Thank you

Regards,

Thao

Reply
0 Kudos
krish290785
Enthusiast
Enthusiast
Jump to solution

ESXi is pretty much Ligh weight. During the Installation, the ESXi would create partitions automatically. The Patitions to hold bootbank (main code), altbootbank, 4 Gigs vfat, store partition for Tools and etc., This would be enough for the ESXi to run and wouldn't require anything else. A total of around 5 G of the space is used and the rest would be left out for you to create datastores to store virtual machines.

From the left out space, Ensure that you have left at least 20 to 30 GB per VM separately to run snapshots during your patch/maintenance cycles.

-Bala Krishna Gali If the above info is useful, please mark answer as correct or helpful.
Reply
0 Kudos
KSethi
Enthusiast
Enthusiast
Jump to solution

Hi Thao,

ESXi 5.5 requires a boot device that is a minimum of 1GB in size. When booting from a local disk or SAN/iSCSI LUN, a 5.2GB disk is required to allow for the creation of the VMFS volume and a 4GB scratch partition on the boot device. If a smaller disk or LUN is used, the installer will attempt to allocate a scratch region on a separate local disk. If a local disk cannot be found the scratch partition, /scratch, will be located on the ESXi host ramdisk, linked to  /tmp/scratch. You can reconfigure  /scratch to use a separate disk or LUN. For best performance and memory optimization, VMware recommends that you do not leave /scratch on the ESXi host ramdisk.

Rgds

KANISHK

sunnythao201420
Contributor
Contributor
Jump to solution

Thank you all very much for the answers.

Regards,

Thao

Reply
0 Kudos