I assign VirtualBox disk image (.vdi) files on a USB stick.
I have found that it is painfully slow.
The reason is easy.
VirtualBox flushes write caches very often.
Even you make dirty_writeback_centisecs and alike very long, the result is same.
Then, how it flushes often?
do sync(2) often? No.
>From an output of strace, it is no.
No sync, no fsync, no fdatasync....
and no O_DIRECT and no O_SYNC ....
How VirtualBox flushes so often?
My question is, how to prevent this flushing.
how to enable (revive) delay-write feature of
Linux USB driver?
--- Okajima, Jun. Tokyo, Japan.
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