@markds we have seen major improvement when booting a vm in uefi, for some reason vms created on vmware with bios are terrible slow on xcp-ng, switching to uefi made them running normal again.
Posts made by rtjdamen
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RE: Poor VM performance after migrating from VMWare to XCP-NG
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RE: Why does the backup use snapshots and not CBT
@olivierlambert i have created a feature request for this over support.
in the meantime i will let u know the results with the current software we run, if this is working as required this can be a good addition for the environment document as well.
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RE: Why does the backup use snapshots and not CBT
@olivierlambert ok, is there a way we can keep an eye on this devepment? shall i open a feature request on this with support or what is the best way to proceed?
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RE: Why does the backup use snapshots and not CBT
@florent quadric currently keeps the snapshot as well but it only contains the cbt metadata, i believe very similar as we are currently running the backups with XOA
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RE: Why does the backup use snapshots and not CBT
I wanted to share my first experiences so far, for 1 single disk vm it works perfect, cbt is created and left only for metadata till the next backup.
For vms with 2 disks i run into some strange behavior, after the bacup job is see one of the 2 disks snapshot (random) at the health page as not connected to a vm and when i run the backup job again it gives an error "source and target are unrelated", the orphan vdi section.
not shure if this is an issue on XCP side or on a bug inside there software.
as i cannot seem to reproduce this issue on single disk vm's i feel like this is an issue with multiple disks. i am contacting there support to see if this is a bug on there end or if this is an issue inside XCP itself.
Keep u all posted on the progess of this tests.
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RE: Why does the backup use snapshots and not CBT
I have my configuration for quadricsoftware up and running, so far so good, works as promised. i will let it run for a few weeks and let u know the results. the CBT is a real game changer so far!
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RE: Why does the backup use snapshots and not CBT
@olivierlambert ok i will share my experience as well.
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RE: Why does the backup use snapshots and not CBT
@olivierlambert yes, maybe the documentation on xcp website can be updated to list them as well.
What is your experience with these backup tools, do u know of companies using them?
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RE: Why does the backup use snapshots and not CBT
@olivierlambert i am currently looking at Quadric Software and storware, Quadric Software is doing the cbt backup exactly as needed, i got there description on the workflow yesterday
*When you run an ABD/hypervisor backup, the A3 will snapshot the VM for the duration of the backup data acquisition phase. After the datea is collected, the snapshot is immediately deleted.
In the case of CBT backups, the snapshot is deleted with the special XAPI command vdi-data-destroy, which frees data associated with the snapshot, but retains metadata, including the block allocation for the disk. This allows us to perform a delta backup the next time, with extremely negligible storage overhead.*
This is what we need
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RE: Why does the backup use snapshots and not CBT
@olivierlambert indeed, what about xenserver compatible backups solutions, can they work on xcp as well? I see we could maybe use agent based backups inside the vms for the larger ones, i will test this with one vm, but need a proper solution in the future, i believe if we can get this to work in xoa that would be the best solution.
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RE: Why does the backup use snapshots and not CBT
Are there any 3th party backup solutions on xcp that support this?
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RE: Why does the backup use snapshots and not CBT
@olivierlambert ok would be great if we can get this working, will be a huge improvement.
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RE: Why does the backup use snapshots and not CBT
@olivierlambert the current backup method is not suitable for larger vms, if i understand correct on xenserver cbt is allready the standard.
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RE: Why does the backup use snapshots and not CBT
@olivierlambert we are further in the process of using xcp, cbt would make a big difference, if u create a backup now on a large and heavy machine u will create a large snapshot during the day, coalesce this snapshot takes hours. If u create a snapshot at ghe start of a backup, copy only changed blocks and then delete the backup u only need to coalesce the small changes created during the backup. For large backups this is a game changer, we currently cannot move large vms to xcp as its backup is not suitable. When will this change? Is this planned?
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RE: Performance differences and higher cpu usage
@olivierlambert ok, will try this on one of the vms as well. what about the VGA switch? does this affect graphics inside the vm?
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RE: Performance differences and higher cpu usage
@olivierlambert good question, we used the builtin feature of XOA.
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Performance differences and higher cpu usage
Subject: Seeking Advice on VM Performance Issues Post Migration to XCP-ng
Hi everyone,
As we wrap up our migration from VMware to XCP-ng, we've encountered some challenges. Notably, a few customers have reported that their VMs are running slower than they did on VMware. While I haven't noticed significant differences in the performance of my own VMs, some do appear to be underperforming. We primarily host Windows Server VMs with Remote Desktop.
We've observed notably higher CPU usage in Chrome and Outlook. This might be related to hardware rendering or how images are displayed. Currently, the VGA switch is off on all our VMs—a default setting applied by XCP-ng during the migration. I'm curious if turning this switch on would improve performance, especially for Remote Desktop usage, although support suggests it would.
Has anyone dealt with similar issues or settings adjustments in Windows VMs with Remote Desktop? Any insights or real-world experiences would be greatly appreciated.
Thank you!
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RE: Limit cpu of specific VM
@olivierlambert in this case, and we see this more there is an application running on this machine thats is having a cpu leak, we asked the customer to fix this but they lack to, as this kind of vm's cause overusage on the host server we would like to hard limit them so they do not cause issues. this is where cpu cap can help.
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RE: Limit cpu of specific VM
@olivierlambert ok so with a vm having 8 cores, i and i woulde like to physical limit it to the use of 4 cores i need to set cap to 400?