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It's a QLogic (or Broadcom) 10Gb SFP+ for iSCSI and SYNC on separated NICs.Could you please clarify what network cards are you using, what vendor?
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| 100% Writes | 100% Reads |
4K | IOPS| MBps| IOPS| MBps|
--------------------|--------|---------|---------|---------|
StarWind disk | 92,915| 362.95| 140,015| 546.93|
Hyper-V host iSCSI | 59,963| 234.23| 169,514| 662.17|
Guest VM vhdx fixed | 20,008| 78.16| 25,936| 101.31|
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| 100% Writes | 100% Reads |
4K | IOPS| MBps| IOPS| MBps|
--------------------|--------|---------|---------|---------|
StarWind disk | 92,915| 362.95| 140,015| 546.93|
Hyper-V host iSCSI | 59,963| 234.23| 169,514| 662.17|
Guest VM vhdx fixed | 52,094| 203.49| 61,297| 239.44|
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Yes, the vhdx is fixed size, the VM is Gen2 using SCSI controller.Oleg(staff) wrote:Hi batiati,
Please try with fixed .vhdx. Please also make sure that you are using SCSI controller for .vhdx connection.
Did you try proposed tweaks?
Please share your findings.I'll try to connect another iSCSI disk to a Vmware host and run some tests with a VM on Esxi, maybe it is not a Hyper-V issue.
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------------------------------------------------------------
| 100% Writes | 100% Reads |
4K | IOPS| MBps| IOPS| MBps|
--------------------|--------|---------|---------|---------|
StarWind disk | 92,915| 362.95| 140,015| 546.93|
Hyper-V host iSCSI | 59,963| 234.23| 169,514| 662.17|
Guest VM vhdx fixed | 52,094| 203.49| 61,297| 239.44|
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| 100% Writes | 100% Reads |
4K | IOPS| MBps| IOPS| MBps|
--------------------|--------|---------|---------|---------|
VMWare VM zeroed | 48,480| 189.38| 97,873| 383.32|
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HKLM\System\CurrentControlSet\Control\StorVsp\IOBalance\Enabled
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| 100% Writes | 100% Reads |
4K | IOPS| MBps| IOPS| MBps|
--------------------|--------|---------|---------|---------|
StarWind disk | 92,915| 362.95| 140,015| 546.93|
Hyper-V host iSCSI | 59,963| 234.23| 169,514| 662.17|
Guest VM vhdx fixed | 57,981| 226.49| 138,365| 540.29|
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I had the same issue again, and I finally realize what I was doing so wrong: I enabled the NTFS Dedup on CSV, and that thing is a big IOPS killer; That was why on a new vhdx I achive a fine performance, because the dedup job wasn't run yet. When I set dedup off and ran the unoptimze job, all VHDX performed as expected.batiati wrote: So, almost solved this issue
I don't know why, but all VMs cloned from that specific .vhdx showed the same performance issue.
I created a new .vhdx file and installed a fresh Windows on it, and now it's much better:
No, this registry trick does not work neither on WS2016 nor WS2019, just on 2012 R2; For both, I had the same issue on capped 4K reads.batiati wrote: So, here is the right registry, changed and tested on 2012 R2, removed and tested again! I will try it again on Windows Server 2019 soon.
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HKLM\System\CurrentControlSet\Control\StorVsp\IOBalance\Enabled
Yep, but I meant the performance penalty on a already deduplicated volume, not during the dedup job execution.Boris (staff) wrote:If I am not mistaken, dedup is configured to be performed once in 24 hours, usually during non-production hours namely because of its IOPS hungry nature
Is Hyper-V in general supported with a Deduplicated volume?
We spent a lot of time to ensure that Data Deduplication performs correctly on general virtualization workloads. However, we focused our efforts to ensure that the performance of optimized files is adequate for VDI scenarios. For non-VDI scenarios (general Hyper-V VMs), we cannot provide the same performance guarantees.
As a result, we do not support deduplication of arbitrary in use VHDs in Windows Server 2012 R2. However, since Data Deduplication is a core part of the storage stack, there is no explicit block in place that prevents it from being enabled on arbitrary workloads.