Re: [PLUG] Copying files to multiple volumes

You can of course extend the boustrophedon heuristic to n drives, if you have the drives, e.g., largest file on drive 1, next largest on drive 2, next two on drive 3, next on drive 2, next two on drive 1, etc. And maybe two drives will suffice if you compress each file before storing it.

At YottaDB (and at GT.M as well), we adopted the convention to add an i to the prefix when referring to the power of two, and to leave it out for powers of 10, and for approximate values. So 992Mi (the limit on the number of blocks in a single database file; a database can extend over an unlimited number of files) means exactly 992×1024×1024 whereas 992M means 992×1000×1000 or something in the vicinity of that number accurate to three significant digits.

Regards

– Bhaskar

On Thu, Oct 29, 2020 at 10:24 AM Walt Mankowski via plug <plug@lists.phillylinux.org> wrote:

Interesting! Of course this is all moot now since they won't come
close to fitting on 2 drives.

Speaking of which, can we as an industry decide whether K,M,G,
etc. refer to powers of 1000 or 1024? The reason I thought it might
fit was because the "4 TB" drive had 4 trillion bytes, whereas all the
other TBs were using 1024^4.

Sigh.

On Thu, Oct 29, 2020 at 09:37:22AM -0400, K.S. Bhaskar via plug wrote:
> Steve –
>
> Yes, at minimal cost, it preserves each file's location on disk, and also
> simplifies restoring as well as searching for files.
>
> Regards
> – Bhaskar
>
> On Thu, Oct 29, 2020 at 2:41 AM Steve Litt <slitt@troubleshooters.com>
> wrote:
>
> > On Wed, 28 Oct 2020 21:33:13 -0400
> > "K.S. Bhaskar via plug" <plug@lists.phillylinux.org> wrote:
> >
> > > You can use a boustrophedon-inspired heuristic that will likely give a
> > > good-enough fit. For two drives, create the same directory hierarchy
> > > on both drives, and sort the file sizes from largest to smallest.
> > > Then put the largest file on disk1 in the directory where it belongs,
> > > the next two on disk 2 in the directories where they belong, the next
> > > two on disk 1, the next two on disk two, and so on. You can extend
> > > this heuristic to n drives.
> >
> > Is the reason for the identical directory structures on each disk to
> > preserve each file's location on the original?
> >
> > SteveT
> >
> > Steve Litt
> > Autumn 2020 featured book: Thriving in Tough Times
> > http://www.troubleshooters.com/thrive
> >

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