Has Parallels looked at performance hit in APFS?

Z

zslg01

Member
The word on the web is that due to the way APFS handles file extents, a VM can create tens of thousands of extent entries in the file representing the VM as time goes on.
For example see the OWC presentation at last year's user conference. The issue can cause a ballooning of access time since APFS is a tree structure that needs to be traversed. The issue also causes massive fragmentation - not an issue on SSD drives but death on HDDs. In fact the recommendation there is don't use APFS on rotating media.
Parallels - any comment? Any help on alleviating this issue?
 
I'm not sure if you're currently using Parallels, but there is a free trial available for you to check out if you are concerned about performance. If you are currently using Parallels, might I ask which program you are experiencing the performance issues in?

In regards to APFS performance and Parallels, they seem to be very positive about it: https://www.parallels.com/blogs/macos-apfs-faqs/ There is only mention of performance increases, if you are using an SSD or flash drive. However an external source says it isn't necessarily recommended on HDDs, unless you need the extra security: https://blog.macsales.com/43043-using-apfs-on-hdds-and-why-you-might-not-want-to/.

If you really do not want it on an APFS drive, you have the option of using it off an external drive / secondary drive (this is what I do).
 
I am a Parallels Pro user. I like some of the APFS features - just not on HDD and not as a VM image file. The way APFS throws extent entries at everything is a problem for a long running VM image. To me it is obvious Apple is moving to an all-SSD, all-iPad/iPhone/MacbookAir way. In fact I am considering moving my server machine off of High Sierra and to Linux since it uses a hard drive for its OS disk.
There are questions I'd like to hear Parallels answer - will they move to APFS snapshots and away from their builtin ones. Will they try and optimize disk storage usage and performance for long running VM images or are they focused on short burst usage for needed apps. I also wonder what their stance is vis-a-vis Apple's rumored move to ARM.
 
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