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Server 2019 Hyper-V Replica make HRL files for excluded disks

Have make Hyper-V VM guest and setup replication, there is 5 disks, 3 of them excluded from replica, but as i see on files system there is created HRL files for all disks of VM, even for excluded. After a replication period (5 sec) send difference for 2 disks of replication on replication server, excluded disks HRLs just deleting by system.

System is on SSD drive, on excluded disks placed temp files, it's double write operation on SSD.

On WS2012R2 there is no such problem.

Is there any fix for this?

windows-server-hyper-v
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MicoMi-MSFT avatar image
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MicoMi-MSFT answered

Hi,
I did a test in my lab and found that only the chosen disks would create the HRL files (only the "test" vhd had HRL).
51933-image.png
Please check if the extra HRL files belong to the excluded disks and provide the screenshot.
Also please check if the server is updated to the latest, if not, please update it and check if there's any third-party software running on the server, if yes, please uninstall them and start the VM again.

Thanks for your time!
Best Regards,
Mico Mi


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Gektor-8328 avatar image
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Gektor-8328 answered

Only VHost-005c is replicated, VHost-005sc is NOT replicated, but if i copy some big size file on VHost-005sc disk, there will be growing HRL file, and it will be deleted after sync time:
51993-%D0%B8%D0%B7%D0%BE%D0%B1%D1%80%D0%B0%D0%B6%D0%B5%D0%BD%D0%B8%D0%B5.png


51994-%D0%B8%D0%B7%D0%BE%D0%B1%D1%80%D0%B0%D0%B6%D0%B5%D0%BD%D0%B8%D0%B5.png



All latest updates installed.
I have try to install a fresh new system - there is same problem (have place in different directories VHDX files):
VHost-001c - replicaed
VHost-001d - excluded
VHost-001e - excluded
All files with growing HRL files.


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Gektor-8328 answered

Maybe magic with Vhost*-*001c in name of VHDX? Can you try same instance with names:
VHost-001c - replicaed
VHost-001d - excluded
VHost-001e - excluded

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Gektor-8328 answered Gektor-8328 commented

And can you try copy some big size file on NOT replicated disks and see, does HRL file size is growing?

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Hi, what do you mean about coping some big size file on NOT replicated disks? Can you please give some instances for better undeestanding your idea?
And this is the screenshot with the same names of your instances and only the chosen disk has HRL:
51838-image.png

Best Regards,
Mico Mi


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image.png (18.4 KiB)

Make VM with 2 dynamical size 100 GB VHDX disks in different locations (for example - different directories):
C:\Hyper-V\VHost-001\Virtual Hard Disks\VHost-001c.vhdx
D:\Hyper-V\VHost-001\Virtual Hard Disks\VHost-001d.vhdx

Then create replication (with send data every 30 sec), and exclude disk:
D:\Hyper-V\VHost-001\Virtual Hard Disks\VHost-001d.vhdx

attach some DVD/Physical Disk/another VHDX to VM and copy files in VM (more than 1 GB) to NON replicated disk:
D:\Hyper-V\VHost-001\Virtual Hard Disks\VHost-001d.vhdx
you will see growing VHDX file and HRL file in this directory:
D:\Hyper-V\VHost-001\Virtual Hard Disks\

Duplicated data with HRL file of non replicated disk will be deleted by system every 30 sec.

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Hi, do you mean copy large files from NON replicated disk to new vhdx?

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MicoMi-MSFT avatar image
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MicoMi-MSFT answered

Hi,
Once the initial replication of a VM is completed, Hyper-V replica will start monitoring the change of each selected virtual hard disk. This is done by mirroring the changes to a HRL file.
You can try to use Resource Monitor and Process Monitor to find the problem area. Using Resource Monitor, you will be able to see which process is making writes to which file which can help you isolate any activity that is not normal. Since Hyper-V Replica tracks all writes, a large temporary file can cause a really large HRL file.
Here is the doc that may be helpful for you:
https://docs.microsoft.com/en-us/virtualization/community/team-blog/2014/20140202-hyper-v-replica-debugging-why-are-very-large-log-files-generated
Since the research that forum can do is limited, if you want to know the root cause, it is suggested to go to open a case in the following link so that a dedicated Support Professional can assist you in a more efficient manner.
https://support.microsoft.com/en-us/gp/customer-service-phone-numbers

Thanks for your time!
Best Regards,
Mico Mi


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Gektor-8328 answered Gektor-8328 edited

I see that you did not understand my question. I did not select disk (exclude it from replication), but hyper-v make mirroring the changes to a HRL file of excluded disk. On Windows Server 2012 R2 i did not seen that problem, it happens only on Windows Server 2019.
I have resolve this problem on WS2019 by connecting physical disk to VM, instead of excluded VHDX, and this resolve my issue with unnecessary HRL files for excluded disks.
But this is insane, to mirror write data for excluded VHDX in Hyper-V Replication.
More insane, that i can't change path for mirrored HRL files, for example - on RAID0 HDD, instead of double writes on SSD, that killing lifespan of SSD twicely and reduce overall speed by growing latency of SSD...

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