I have a USB3 5TB hard drive formatted as HFS+ with FileVault (full disk encryption) that I am using with MacOS Mojave. It is about 60% full and is getting slower and slower as I write additional files to it by copying files and folders in Finder. I am getting write speeds of between 80MB and 300MB per minute depending on whether the folders I drag contain small or large files. (Normally, unencrypted, this drive would write several gigabytes per minute in Finder copy operations, e.g.10 to 40 times faster.) I have seen this problem in systems ranging from Yosemite and newer, that FileVault hard drives slow down a lot as they fill, even if only half full.
I looked at Activity Monitor in my computer (with All Processes view) while the finder is copying files to the encrypted disk. I find both the rate of CPU usage and disk usage to be slow, looking like the computer is not burdened, but yet the copying is very slow.
I observed in Activity Monitor that it appears that the process copying the data to my hard drive is called DesktopServicesHelper. I find its disk usage in bytes written corresponds to the amount of data copied to the drive, and its CPU usage is almost nothing, implying no burden to compute the encryption.
This made me think the process was being run at a very low priority even though the computer was otherwise idle. I tried using the unix renice command ("sudo renice -n -10 -p [Process ID of DesktopServicesHelper]") to increase the priority of DesktopServicesHelper intending to make the computer work harder to get my copying and encrypting done faster, but it made no difference.
It seems the computer is under a burden that is not visible in Activity monitor while copying files to encrypted volumes or that the computer is unneccesarly lowering the priority. How can I find out exactly what is causing the slowness and increase priority of appropriate processes to make the computer work harder to copy the files faster? It's OK if the fan would run if it gets the copying done in reasonable time.
Is there anything I can do to diagnose this better, identify the bottleneck, and/or speed up writes? Would it be significantly faster to use some other tool or command to copy my files and folders to an encrypted volume?
Thanks
I looked at Activity Monitor in my computer (with All Processes view) while the finder is copying files to the encrypted disk. I find both the rate of CPU usage and disk usage to be slow, looking like the computer is not burdened, but yet the copying is very slow.
I observed in Activity Monitor that it appears that the process copying the data to my hard drive is called DesktopServicesHelper. I find its disk usage in bytes written corresponds to the amount of data copied to the drive, and its CPU usage is almost nothing, implying no burden to compute the encryption.
This made me think the process was being run at a very low priority even though the computer was otherwise idle. I tried using the unix renice command ("sudo renice -n -10 -p [Process ID of DesktopServicesHelper]") to increase the priority of DesktopServicesHelper intending to make the computer work harder to get my copying and encrypting done faster, but it made no difference.
It seems the computer is under a burden that is not visible in Activity monitor while copying files to encrypted volumes or that the computer is unneccesarly lowering the priority. How can I find out exactly what is causing the slowness and increase priority of appropriate processes to make the computer work harder to copy the files faster? It's OK if the fan would run if it gets the copying done in reasonable time.
Is there anything I can do to diagnose this better, identify the bottleneck, and/or speed up writes? Would it be significantly faster to use some other tool or command to copy my files and folders to an encrypted volume?
Thanks