Re: DD not working--SUCCESS!

How would you go about estimating a decent blocksize (other than by
testing)? My first instinct would be to go for some percentage of
the drive's cache. (And it had better be a factor of the amount you
want to copy I suppose.)

--
imalone

Available RAM. Use as big a block size as can possibly be read into
RAM (once you start caching to a drive you just as well be writing to
the destination drive otherwise you slow it down even more). We
played around with this a while back and it certainly makes a
difference (stands to reason as was already explained).

The one caveat would be if there are errors on the drive. If that is
the case, a full block is dropped (so if your block size is 4096
bytes, then 4K gets dropped instead of 512 bytes - now imagine
dropping a 256 meg block of data...). ddrescue will use two block
sizes - a larger one and a smaller one. If it hits an error it drops
back to the smaller one until it gets pass the error and then ramps
back up to the larger block size.

Jacques

--
fedora-list mailing list
fedora-list@xxxxxxxxxx
To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list

Relevant Pages

  • huge box of ram?
    ... say) that can hold a huge amount of ram, ... The application is a high traffic database ... cache. ...
    (comp.arch.storage)
  • [ot] free memory
    ... What is the best way, under GCC based compilers, to get amount of free ... memory, both RAM that OS can gave to my application, and total memory that ... I need to know +/- how much RAM is free and available for my application, ... to optimize it's caching code (it is a bad idea to cache all data that can ...
    (comp.lang.cpp)
  • Re: efficacy of Linux w/o swap
    ... |> dedicated purpose that will use Linux and commodity hardware. ... | I suppose you could lock into RAM, ... can account for such an extreme amount of time. ... then evetually complete the switch. ...
    (comp.os.linux.development.system)
  • Re: xp pro blue screen
    ... Insufficient RAM. ... the amount of RAM, and performance seems to suffer quite badly if and ... Windows Task Manager is basically useless for this type of assessment ...
    (microsoft.public.windowsxp.help_and_support)
  • Re: xp pro blue screen
    ... Insufficient RAM. ... the amount of RAM, and performance seems to suffer quite badly if and ... Windows Task Manager is basically useless for this type of assessment ...
    (microsoft.public.windowsxp.help_and_support)