Alasdairb
asked on
Will a snapshot save me from a damaging CHKDSK?
Hello,
as a reasonably inexperienced person with VMware, I have an issue with a VM. It is an SBS2011 server in production and the last few days there is an error in the event logs about the hard disk having a bad block. Since then our Veeam backups have failed with a CRC error. CHKDSK with no parameters (i.e. no attempt to fix anything) shows 8k in bad blocks.
I know chkdsk can be destructive to data, my worry is if I run it there is a very small possibility the VM will not boot afterwards - unlikely but that would be just me luck. To minimise downtime I was wondering if I could protect against this by taking a snapshot beforehand. If the VM gets broken by the chkdsk I could just revert to snapshot, would that be correct?
Thanks a lot.
Alasdair Barclay
as a reasonably inexperienced person with VMware, I have an issue with a VM. It is an SBS2011 server in production and the last few days there is an error in the event logs about the hard disk having a bad block. Since then our Veeam backups have failed with a CRC error. CHKDSK with no parameters (i.e. no attempt to fix anything) shows 8k in bad blocks.
I know chkdsk can be destructive to data, my worry is if I run it there is a very small possibility the VM will not boot afterwards - unlikely but that would be just me luck. To minimise downtime I was wondering if I could protect against this by taking a snapshot beforehand. If the VM gets broken by the chkdsk I could just revert to snapshot, would that be correct?
Thanks a lot.
Alasdair Barclay
If the system crytical data is already in bad blocks then your system would not boot now. Means the chances that your system won’t boot are minimal.
chkdsk was designed before VMs and mostly works as if the disk is physical.
I recommmend powering down the server and taking a copy of the virtual disk. then power back on and run chkdsk. Worst case, use the copy to get the server booted.
Also, I'd usually say tae backups first but you may not be able to. I recommend taking a copy of anything critical to your business as far as is posisble, just in case. a further reason for copying the virtual disk.
Worth checking why youve got bad blocks in the first place too.
I recommmend powering down the server and taking a copy of the virtual disk. then power back on and run chkdsk. Worst case, use the copy to get the server booted.
Also, I'd usually say tae backups first but you may not be able to. I recommend taking a copy of anything critical to your business as far as is posisble, just in case. a further reason for copying the virtual disk.
Worth checking why youve got bad blocks in the first place too.
Good afternoon,
You can perform a snapshot with the Quiesce guest file system option.
Remember that if you choose this type of snapshot the vm should be on and have the vmware tools installed, since they use a service to communicate with Windows VSS and perform an instantaneous operation within the operating system.
Another option that you can perform is to turn off the VM and export it to OVA template and you will have another backup of your VM.
I remain attentive to your comments.
Regards...
You can perform a snapshot with the Quiesce guest file system option.
Remember that if you choose this type of snapshot the vm should be on and have the vmware tools installed, since they use a service to communicate with Windows VSS and perform an instantaneous operation within the operating system.
Another option that you can perform is to turn off the VM and export it to OVA template and you will have another backup of your VM.
I remain attentive to your comments.
Regards...
A snapshot contains only the data from the point that it was created onward, not complete VM data.
Either way, no
Either way, no
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But if you have a veeam backup (hopefully not at the same ESXi machine), you should be able to recover at least to the state of the veeam backup.