> > RAID controllers do not have half a terabyte of RAM.
It makes a lot of difference, and in addition raid controllers (good
ones) respect barrier ordering in their RAM cache so they'll take tags or
similar interfaces and honour them.
Either you keep a mirror in sync and get normal data rates or you keep
the mirror out of sync and then you need to sort your writeback process
out to preserve ordering.
If you want ramback to be taken seriously then that is the interesting
problem to solve and clearly has multiple solutions if you would start to
take an objective look at your work.
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