× NETGEAR will be terminating ReadyCLOUD service by July 1st, 2023. For more details click here.
Orbi WiFi 7 RBE973
Reply

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware

kck126
Aspirant

ReadyNAS 4220 - NFS vs. iSCSI - VMware

NETGEAR Community,

 

We are in the process of changing our VMware infrastructure and I have run into a few performance questions regarding our ReadyNAS setup.  I am hoping the experienced members can offer some advice and insight.

 

Currently we have two ESXi 5.5 hosts running virtual machines from both internal (SAS) storage and a ReadyNAS 3100 using NFS (default settings).  Our main (critical) database servers are running on the internal datastores.  Our lightweight virtual machines are running from the 3100.  We have purchased a ReadyNAS 4220 and setup 10Gbe connections to the two ESXi hosts.  We would like to setup centralized storage for all of our virtual machines and eliminate the need for local storage on the ESXi hosts.

 

I have done a great deal of research and testing.  However, this has led me to a great deal of confusion.  The ReadyNAS 4220 has 12 – WD 2TB Black drives installed in raid 10.  I have been very impressed with the performance I am getting while testing iSCSI.  However, the NFS write speeds are not good (no difference between a 1Gb and 10Gb connection and well below the iSCSI).

 

I understand that this is a potential limitation of NFS in general.  The NFS performance problems are resolved by enabling async, although I have read that this can lead to data corruption and problems.  Ultimately we will see a performance increase running the VMs from the 4220, but I don’t want to risk a major corruption problem if we are using async to gain the desired performance with NFS.

 

The ESXi hosts are connected to battery backups and will automatically shut down all VMs in the event of a power failure.  The ReadyNAS is not setup to shutdown (but I am looking into a solution).  So my essential question is:  Should I enable async to gain the performance using NFS, or restructure our setup and use iSCSI?  I like the flexibility NFS offers and have read it is the recommended setup for VMware, but I will need the performance achieved by enabling async to make it a viable solution.

 

I greatly appreciate any help/insight the community can provide and will be more than happy to provide additional details as needed.  Thank you,

 

Kevin

Message 1 of 7

Accepted Solutions
kohdee
NETGEAR Expert

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware

Yes, you should enable async if you plan to use NFS. async'll hold lots of your data in RAM and write it nicely to the disks when it has time to. Otherwise, NFS is demanding the ReadyNAS to sync the file system before taking on more data.

I don't like NFS as much because of how bad you can fragment the vmdks on btrfs.

 

I would recommend:

iSCSI

Thick LUN

No snapshots

Sync Writes disabled

No bit rot protection

Do not use more than 80-85% of total usable space when creating your environment. 

Schedule defrag/balance to run on weekends or every other weekend. 

 

It's what I use in my VMware environment and still working hard  🙂

View solution in original post

Message 2 of 7

All Replies
kohdee
NETGEAR Expert

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware

Yes, you should enable async if you plan to use NFS. async'll hold lots of your data in RAM and write it nicely to the disks when it has time to. Otherwise, NFS is demanding the ReadyNAS to sync the file system before taking on more data.

I don't like NFS as much because of how bad you can fragment the vmdks on btrfs.

 

I would recommend:

iSCSI

Thick LUN

No snapshots

Sync Writes disabled

No bit rot protection

Do not use more than 80-85% of total usable space when creating your environment. 

Schedule defrag/balance to run on weekends or every other weekend. 

 

It's what I use in my VMware environment and still working hard  🙂

Message 2 of 7
mdgm-ntgr
NETGEAR Employee Retired

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware

I would recommend connecting the ReadyNAS units to a UPS, especially if you wish to use NFS and enable async. We use NUT (Network UPS Tools) to share UPS shutdown commands between our NAS units.

Message 3 of 7
kck126
Aspirant

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware

@kohdee

 

Thank you very much for taking the time to provide helpful information.  Based on your post and further research I am going to use iSCSI.  Do you have a recommendation or preference for iSCSI "Sync Writes?"  I have not had time to test whether or not sync writes have a significant impact on iSCSI performance.  Thank you,

 

Kevin

Message 4 of 7
kck126
Aspirant

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware

@mdgm-ntgr

 

Thank you very much for taking the time to respond.  We do have the ReadyNAS connected to a rackmount APC UPS, but do not have it configured to automatically shutdown in the event of a power failure.  My initial approach is to make sure the ESXi guests and hosts have shutdown gracefully prior to the ReadyNAS.  I will look at NUT to see if it is a viable solution for our scenario.  Thank you,

 

Kevin

Message 5 of 7
mdgm-ntgr
NETGEAR Employee Retired

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware

For Virtualisation you should disable Sync Writes. Again safe shutdown using the UPS is strongly recommended when disabling sync writes.

Message 6 of 7
kohdee
NETGEAR Expert

Re: ReadyNAS 4220 - NFS vs. iSCSI - VMware


@mdgm wrote:

For Virtualisation you should disable Sync Writes. Again safe shutdown using the UPS is strongly recommended when disabling sync writes.


 

I updated my original post to include Sync Writes to disabled. Forgot about this one.

Message 7 of 7
Top Contributors
Discussion stats
  • 6 replies
  • 12041 views
  • 2 kudos
  • 3 in conversation
Announcements