VMware Cloud Community
TonyJK
Enthusiast
Enthusiast
Jump to solution

Reasons for SLOW create / remove snapshots

Hi,

We are running ESXi 5.1 Hosts in a cluster.

We have added a number of VMs to the cluster and thus the Memory Utilization of each ESXi Host is around 60%.  Network Administrator also performs a network change lately (He says it should not affect VMWare).

However, we find that it takes much longer for us to create / remove snapshot.  Just wonder whether it may be due to Network Issue OR just we are running out of Memory in the ESXi Hosts / SAN Performance ?

Your advice is sought.

Tags (1)
Reply
0 Kudos
1 Solution

Accepted Solutions
Alistar
Expert
Expert
Jump to solution

Hello,

Before we dive deeper, the main question here is - what exactly was the scope of this network change? This seems that something was changed on the network that impacts the connection between ESXi hosts & the shared storage's network interfaces. Also you should make sure that the change has not affected the VAAI availability on your storage as well, since snapshots are manipulated directly on the disk arrays. A delta disk is created, the base disk is made read only and all writes are then performed on the delta disk. The delete snapshot commits these changes. But of course you should check your SAN performance if it is not hitting any bottleneck by coincidence (CPU, Memory, I/Os).

If you get the information about what has changed, we can help you further.

Stop by my blog if you'd like :slightly_smiling_face: I dabble in vSphere troubleshooting, PowerCLI scripting and NetApp storage - and I share my journeys at http://vmxp.wordpress.com/

View solution in original post

Reply
0 Kudos
2 Replies
Alistar
Expert
Expert
Jump to solution

Hello,

Before we dive deeper, the main question here is - what exactly was the scope of this network change? This seems that something was changed on the network that impacts the connection between ESXi hosts & the shared storage's network interfaces. Also you should make sure that the change has not affected the VAAI availability on your storage as well, since snapshots are manipulated directly on the disk arrays. A delta disk is created, the base disk is made read only and all writes are then performed on the delta disk. The delete snapshot commits these changes. But of course you should check your SAN performance if it is not hitting any bottleneck by coincidence (CPU, Memory, I/Os).

If you get the information about what has changed, we can help you further.

Stop by my blog if you'd like :slightly_smiling_face: I dabble in vSphere troubleshooting, PowerCLI scripting and NetApp storage - and I share my journeys at http://vmxp.wordpress.com/
Reply
0 Kudos
TonyJK
Enthusiast
Enthusiast
Jump to solution

Since our LUN are based on EMC CX SAN via FC Switch, I don't know how the network change will affect the shared storage network interface (Please correct me if I am wrong).  OR which network interface is for SAN Connection ?

He doesn't mention what has been changed and just reply it is not caused by the network change.

Basically, the routers has been changed and VLAN has been created.  However, he still keeps the existing server IP (ESXi Hosts / VMs and physical servers) addresses.  It appears that workstation IP address is no longer provided by DHCP Server (He assigns a particular VLAN for workstations and dynamic IP is provided by the router, I suppose).

Reply
0 Kudos