Slow write speed on newer WD 10TB Red drives
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Hi,
I experienced very slow write speed ~ 30MB/s on new WD 10TB Red or 8TB Red drives when encrypted using the latest version of VC. My system is Intel Core i7 8700k. Read speed seem to be ok, its only during write that there is an issue.
I get the same slow speed on fully encrypted partition using quick format, or on encrypted container. When unencrypted, the same drive gives ~120-130MB/s write speed.
Other previously encrypted WD 8TB Red drives using an older version of VC (can't remember the version but probably 1.6 or earlier) seems to have normal write speed of ~90-120MB/s, the problem is only when encrypting a new disk using a newer version of VC.
any suggestions?
Last edit: AdrianG 2019-07-21
Are you using a cascade cypher? What is going on with the CPU when you are doing heavy writes? Is it anywhere close to 100% on all cores?
No I tested using the regular AES cypher, and the CPU usage is very low <3%. and the test benchmark with AES is giving me 7.4GB/s.
First I tought it could be a driver issue for the disk, but I am using the same microsoft standard driver on all disks so I can't explain the slow write.
Edit : I tried the beta version 1.24 Beta5 and the problem seems to have been magically resolved
I would like to understand what change in the beta 5 version restored the write speed to its normal
value, but I can't find anything exept this one:
but for me I get 3x the speed so I dont think this is it...
I am also at a loss to explain it. The write speed, how are you measuring it? Is this through VeraCrypt when it is encrypting?
I use the windows performance monitor while copying large files from one encrypted hard disk to another encrypted hard disk, also another tools that measure total system disk read and write speed.
The read speed from the source hard disk is very fast > 100MB/s , but the write speed on the destination is slow < 30MB/s while the CPU usage remains very low. At some point the windows cache will fill up and the source disk read speed will slow down to match the destination.
Last edit: AdrianG 2019-07-21
After some time, I realized that I still had the slow write speed issue with WD 10TB and 8TB RED drives with write speed around <35MB/S , and recently 12TB WD with write speed <50MB/S.
The problem is less obvious on WD 8TB Gold drives but still visible as I get < 85MB/s instead of 120MB/s. Even if the destination disks have been agressively defragmented, leaving a big chunk of free space at the begining of the drive, the problem is still threre. What is strange as the CPU barely goes over 3%.
The problem seem to arise after a couple of minutes, and can be deceiving as you have the initial burst of speed at 150MB/s-180MB/s for one minute, and then a gradual slow down until you reach a cruise speed of 30MB/s.
Could this be related to IRP issue for NVME SSD drives as described in this thread? https://github.com/veracrypt/VeraCrypt/issues/136. ? Just trying to understand.