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Elevator Sorted Write-back - Request for Enhancement

Posted: Sun Dec 08, 2019 8:22 pm
by rcamarda390
Back in the day, I used DPT caching controller HDA for SCSI. They had a whopping 16MB of cache (and where OMG expensive in the late 80's) . They had a feature of Elevator Sorted Write-back:

From their user manual: "Data is written to disk in order of increasing block address, minimizing both physical disk seeks and rotational latency. This feature, called Elevator Sorted Write-back, eliminates much of the head thrashing commonly associated with disk-intensive operating systems like Novell NetWare, Windows NT and UNIX. By elevator sorting the sectors in cache, the average write access time to the drive may be reduced from the normal 11ms (seek + rotation) time, to between 1 and 5ms."

I think this could be a great feature when writing to spinning disks
I currently use PrimoCache on a 10 y/o PC with 16GB of memory and modern SSDs w/ spinning disks. I can def tell improved performance.
My replacement PC will have PrimoCache in mind for memory capacity and a tiered storage solution.
Thanks in Advance!

Re: Elevator Sorted Write-back - Request for Enhancement

Posted: Mon Dec 09, 2019 10:06 am
by Support
With Defer-Write enabled, PrimoCache does write deferred data in order of increasing block address and combining small writes to a large sequential write. :)

Re: Elevator Sorted Write-back - Request for Enhancement

Posted: Mon Dec 09, 2019 10:56 am
by rcamarda390
Cool, I knew about deferred write (which I use). I didnt know you also did the sequential write.
Thanks!

Re: Elevator Sorted Write-back - Request for Enhancement

Posted: Tue Feb 11, 2020 4:58 pm
by minhgi
support wrote: Mon Dec 09, 2019 10:06 am With Defer-Write enabled, PrimoCache does write deferred data in order of increasing block address and combining small writes to a large sequential write. :)
Didn't want create another post since the my question is related to the sorted writeback. I'm using Diskeeper wit intelliwrite enable along with deferred write. Will the two features hinder each other performance? Should one of them will need to be disable?

Re: Elevator Sorted Write-back - Request for Enhancement

Posted: Thu Feb 13, 2020 3:34 pm
by Support
According to Diskeeper description of its intelliwrite tech, theoretically we think these two features can work together. However, we haven't tested and verified this. Need more time, sorry.

Re: Elevator Sorted Write-back - Request for Enhancement

Posted: Fri Feb 14, 2020 1:29 pm
by minhgi
support wrote: Thu Feb 13, 2020 3:34 pm According to Diskeeper description of its intelliwrite tech, theoretically we think these two features can work together. However, we haven't tested and verified this. Need more time, sorry.
yeah. I didn't see any conflict or performance lost using the combination for over 3 years since defer write was introduced. Just curious.
thks