Cluster and MFT size for Seagate 750GB

  • Thread starter Thread starter ChrisLampson
  • Start date Start date
C

ChrisLampson

I have a Seagate Barracuda 750GB SATA II drive that I want to use as a
storage drive (Windows will not be on this drive).

The drive will hold approximately 300,000 files, maybe more, on NTFS:
- mostly JPG (approx 6mb each)
- and about 1/10 PSD files

The drive will be completely scanned several times a day by automatic
backup software.


My questions are:

1. What cluster size should I format the drive at (file allocation
unit)?
From what I've read, the default (4kb) is the best option, but I'm
Click to expand...
unsure.

2. What size (or how many files) should the MFT be/hold?
Yes, I've googled;
I know about the NtfsMftZoneReservation registry key and have set it to
4 (50%) without any obvious or tangible results.
Yes, I also use Diskeeper, but on a blank drive the recommended size is
22 million file records.
So I'm asking what to put in the manual size input box (number of
files).


Thanks in advance, I really appreciate it.
Microsoft is really lacking in speifics in their documentation.
 
How are you going to store 300,000 6mb files on a 750GB disc? You're
short by about 1 terabyte according to my quick calculations.

Of course it's early'ish morning so maybe I'm still half asleep and
completely off on my calculations.

This is off the top of my head and highly subject to corrections but it
seems to me that with all the NTFS file properties "bells and whistles"
used a file record in the MFT occupies up to 16kb. Do the math. You
want to reserve 350GB for a 4.5 gb file table. Double that for the MFT
mirror and you get about 9gb, lets round it up to 10 gb. The MFT size
that you propose would be more appropriate for storing 25 million 16kb
files than 300,000 6MB files!

Leave the MFT reserved area to 12.5% and leave the clusters to 4KB.
Changing the default clusters to a larger size for relatively small 6mb
files is completely unnecessary. Other than for humongous SQL files
there is little need to fuss with the cluster size and for small 6mb
files the performance gains will be minuscule at best. Changing the
cluster size may also present defragmentation problems for the built in
defrag tool.

John
 
Thanks for the reply.

Your inner calculator serves you well.

First, the (my estimated) *average* JPG size is around 6mb, but ranges
anywhere from 1mb - 7mb. PSDs range from 20kb - 20mb.

My mistake; the 300,000 files came from a Windows file count, but I
forgot to mention that at least 75% of all the files have an equivalent
hidden 1kb Macintosh-created file.
(ie. "picture001.jpg" has a 1kb "._picture001.jpg")
Those things have always driven me crazy...

In reality I think there's about 132,000 files.


Thanks.
 
Those 1 kb mac files would be stored in the MFT but even those 225,000
little itty-bitty things would hardly use up any significant space in
the MFT on such a large disc, they would make up about .25 GB, not much
in the grand scheme of things. Also, earlier I made reference to the
MFT mirror and I incorrectly added it's size to the MFT. The MFT mirror
is a copy of the first 16 records in the MFT and it is stored in the
middle of the volume. The MFT mirror is a backup that is used to repair
the MFT if it is damaged or becomes corrupt.

One way or the other the default 12.5% MFT size is the best for you to
use on the disc. It will be more than enough and I dare say that you
will never exhaust it. I have an 80 GB drive with over 300,000 files on
it and the MFT is nowheres near to being full, I don't even think that
it's close to the 50% usage mark.

Keep this in mind. If the MFT runs out of space it will appropriate
itself of additional space on the disc so that it can grow. This is the
fragmentation that most people think of when they think of the MFT and
performance issues. In most cases that is not why the MFT becomes
fragmented. The space issue is a two way street, if the disc in getting
full and if the files need additional storage space, the MFT will relax
it's rules and allow files to "steal" space from the MFT, that is
usually how the MFT ends up fragmented. If you reserve 50% of the disc
for the MFT it's an almost sure shot bet that the files will need
additional space long before the MFT is anywheres near the 10% usage
mark. The MFT will relent and cede space to the files and become
fragmented, an absolute given in your scenario, a bet that can be taken
to the bank before payout! It takes many, many, many file records to
fill up the MFT and have it overrun its alloted space and become
fragmented. As I said earlier this usually happens when you store many
tiny little files of a few kilobytes, with larger files for all intents
and purposes it's a non issue. Keep your MFT to the default 12.5% of
disc space.

John
 
Back
Top