Which hdd mode to choose for best speed?

Question

Hard disks

On one of the VMs, I launched Debian 11, I’m not quite satisfied with the speed of the disk (ssd)
now it’s set in the disk properties No cache
I didn’t find anything sensible in the manual, advise plizz which mode to choose?
screen is attached.
Thank you!

Answer 1

not quite satisfied with the speed of the disk

What kind of speed do you not like? Write speed or read speed?

• No cache (current) is a balance of speed and security. The recording speed will be higher, because. Host Page Cache is disabled and Disk Write Cache is enabled.
  
• Write through is also a balance of speed and security. But the reading speed will be higher, because. here, on the contrary, Host Page Cache is enabled, and Disk Write Cache is disabled.
  
• Direct sync is the most secure, but also the slowest. both caches are disabled.
  
• Write back is fast, both caches are enabled, but there is a risk of data loss, for example, when the power is turned off. Previously, he worked in such a mode that he informed the application that all the data had already been recorded, but in fact continued to write in the background. Because of this, it could show unrealistic IOPS. Why you have two options there - I won’t say right off the bat, you need to study it.
  

In any case, you can test read io, write io, and IOPS for all options on your typical workload.
In general, I tend to think that a radical acceleration will most likely require changing the SSD, for example, to a server model.
- UPD. /ps-
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Answer 2

On one of the VMs, I launched

In fact, in the comments, they missed the most important point.
And how is PVE itself installed? Or rather, how the place for the storage of the VMs themselves is organized.
best choice -
if internal disks - zfs/btrfs, bypassing iron raid
if storage - lvm over iscsi