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Virtualbox VMs freeze unter heavy I/O load (fix included)

VirtualBox, VM config and HDD images.
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Virtualbox VMs freeze unter heavy I/O load (fix included)


Post by Colani1200 »

Hi all,

I encountered a problem with virtualbox VMs when the option "Use Host I/O Cache" is not enabled, which is the default setting for Windows guests. The VM will freeze under heavy I/O load, this is reproducable for example during a Windows 10 installation when stuff gets copied. In the log you will find something like this:

Code: Select all

00:04:05.264286 AIOMgr: Host limits number of active IO requests to 256. Expect a performance impact.
00:04:05.607651 AIOMgr: I/O manager 0x00000806fc51e0 encountered a critical error (rc=VERR_FILE_AIO_NO_REQUEST) during operation. Falling back to failsafe mode. Expect reduced performance
00:04:05.607730 AIOMgr: Error happened in /usr/ports/emulators/virtualbox-ose/work/VirtualBox-5.2.44/src/VBox/VMM/VMMR3/PDMAsyncCompletionFileNormal.cpp:(1673){int pdmacFileAioMgrNormal(RTTHREAD, void *)}
00:04:05.607734 AIOMgr: Please contact the product vendor 
The solution is to tweak a couple of sysctl paramters, as found in these old bug reports: ... ?id=212128 ... ?id=168298

I my case, these settings did the trick, where vfs.aio.max_aio_queue_per_proc is the most relevant one

Code: Select all

Maybe this should be adjusted in the default configuration of XIgmaNAS.
Last edited by Colani1200 on 27 Aug 2020 11:48, edited 1 time in total.

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Re: Virtualbox VMs freeze unter heavy I/O load (fix included)


Post by cookiemonster »

Thanks for contributing
Main: Xigmanas x64-full-RootOnZFS as ESXi VM with 24GB memory.
Main Host: Supermicro X8DT3 Memory: 72GB ECC; 2 Xeon E5645 CPUs; Storage: (HBA) - LSI SAS 9211-4i with 3 SATA x 1 TB in raidZ1, 1 x 3 TB SAS drive as single stripe, 3 x 4 TB SAS drives in raidZ1.
Spare1: HP DL360 G7; 6 GB ECC RAM; 1 Xeon CPU; 5 x 500 GB disks on H210i
Backup1: HP DL380 G7; 24 GB ECC RAM; 2 Xeon E5645 CPUs; 8 x 500 GB disks on IBM M1015 flashed to LSI9211-IT

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