Messages in this thread | | | Date | Thu, 21 May 1998 12:57:36 -0500 (EST) | From | "Mark H. Wood" <> | Subject | Re: blocksize > 4K in ext2 ? |
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On Thu, 21 May 1998, Rik van Riel wrote:
> On Wed, 20 May 1998, Sieger Ralf AI wrote: > > > I currently developing a fs which supports among other things > > fragmentation. This means for better throughput I want to use the highest > > possible blocksize. So if someone has an solution to this limit I would > > cheer. > > It's simple. Use 4kB blocks for I/O, and use multiple blocks > for on-disk allocation. > ie: > - you do I/O in multiple 4kB chunks > - you allocate disk space per 256 4kB chunks > > This way, you have 1MB disk blocks. And if you use the > ext2fs preallocation scheme, you can even free the 4k > blocks which aren't used by the file when the file is > closed...
What do you do with the freed 4k blocks? Novell has one answer -- somehow they "suballocate" this unused space, packing several small files into a single block. When free blocks run short, though, the machine goes into a tailspin looking for spare sub-blocks and does very little else. (Axe one big file and your responsiveness comes right back...once your delete request get serviced.)
-- Mark H. Wood, Lead System Programmer mwood@IUPUI.Edu Nothing is so dangerous as being too modern. One is apt to grow old-fashioned quite suddenly. -- Oscar Wilde
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