#1 Global Leader in Data Resilience
#1 Global Leader in Data Resilience
BACK TO KB LIST

Slow Restore Performance With Direct SAN Mode

KB ID: 2052
Product: Veeam Backup & Replication
Published: 2015-07-08
Last Modified: 2022-11-11
mailbox
Get weekly article updates
By subscribing, you are agreeing to have your personal information managed in accordance with the terms of Veeam's Privacy Notice.

Cheers for trusting us with the spot in your mailbox!

Now you’re less likely to miss what’s been brewing in our knowledge base with this weekly digest

error icon

Oops! Something went wrong.

Please, try again later.

Challenge

When performing a Full VM Restore or Virtual Disk Restore using Direct SAN Restore, the performance may be sub-optimal when the restored Disk Type Setting is set to Thick (lazy zeroed).

Cause

When using Direct SAN to restore a disk with it's disk type set to Thick (lazy zeroed), overall restore performance can be affected because of repeated disk manager API calls to ClearLazyZero and AllocateBlock.

Solution

Option 1: Use 'Thick (eager zeroed)' Disk Type

When restoring via Direct SAN, disks must be restored as Thick, either lazy zeroed or eager zeroed. Performance has been shown to be much higher when using the eager zeroed option1.

Entire VM Restore

On the Datastore tab of the Full VM Restore wizard, use the Disk Type button in the bottom-right corner to set the restored disk type to "Thick (eager zeroed)."

FullVMEager
Virtual Disk Restore

On the Disk Mapping tab of the Virtual Disk Restore wizard, use the Restored disk type dropdown box to select "Thick (eager zeroed)."

VirtDiskEagerZero

Option 2: Use Network or Virtual Appliance Transport Mode

If you'd prefer to restore the disk as Thick (lazy zeroed), performance can be improved by using the "Picky proxy to use" option in the Full VM Restore and Virtual Disk Restore wizards to select either a proxy that does not have Direct SAN capability or a proxy that has been manually configured to use either Virtual Appliance or Network transport mode.

Additionally, simply selecting the disk type Thin will force the restore to use any other transport mode because Direct SAN cannot restore disks as Thin provisioned.

To submit feedback regarding this article, please click this link: Send Article Feedback
To report a typo on this page, highlight the typo with your mouse and press CTRL + Enter.

Spelling error in text

This site is protected by hCaptcha and its Privacy Policy and Terms of Service apply except as noted in our Privacy Policy.
Thank you!

Thank you!

Your feedback has been received and will be reviewed.

Oops! Something went wrong.

Please, try again later.

You have selected too large block!

Please try select less.

KB Feedback/Suggestion

This form is only for KB Feedback/Suggestions, if you need help with the software open a support case
By submitting, you are agreeing to have your personal information managed in accordance with the terms of Veeam's Privacy Notice.
This site is protected by hCaptcha and its Privacy Policy and Terms of Service apply except as noted in our Privacy Policy.
Verify your email to continue your product download
We've sent a verification code to:
  • Incorrect verification code. Please try again.
An email with a verification code was just sent to
Didn't receive the code? Click to resend in sec
Didn't receive the code? Click to resend
Start using Veeam:
Download the product
&
Activate the license key
Thank you!

Thank you!

Your feedback has been received and will be reviewed.

error icon

Oops! Something went wrong.

Please, try again later.