[clug] advice on drives for raid

Brett Worth brett at worth.id.au
Wed Aug 13 11:03:58 GMT 2008


Nemo wrote:

> I'm in the process of building up a new machine to be the personal file
> server I need it to be - and I'm thinking of going down the "multiple
> 1TB drives in a raid5" configuration. 

I've a more cost effective solution for you.

If you're after 2.7TB then all you need to do is create 384 gmail accounts with names like 
nemo000 nemo001 nemo002 ... nemo383.  Each account gives you 7026Mbytes of mail storage so 
384*7026 = 2.7TB.

Then you download and install gmailfs:

      http://richard.jones.name/google-hacks/gmail-filesystem/gmail-filesystem.html

Create a top level directory:

	mkdir /gmailfs

You then create 384 individual mount points and mount all your accounts to these mount points:

I=0
while :
do
	DNAME=`printf "nemo%03d" $I
	I=`expr $I + 1`
	mkdir /gmailfs/$DNAME
	mount -t gmailfs /usr/local/bin/gmailfs.py //gmailfs/$DNAME -o username=$DNAME, 		 
password=gmailpass, fsname=$DNAME
	# make the datafiles
	dd if=/dev/zero of=/gmailfs/$DNAME/datafile bs=1024k count=7026
	DEVS="$DEVS /gmailfs/$DNAME/datafile "
done

Now just create a stripe across all these files and mount that file onto your final 
mountpoint.

# mdadm --create /dev/md0 --level=0 --raid-devices=384 --loop-mode $DEVS
# mkfs -j /dev/md0
# mkdir /data
# mount /dev/md0 /data
# df -h /data
/dev/md0              2.7T   2.4M  2.7T  0% /data

Too easy!!

This way you don't even have to back it up because google.com will back it up for you.

Now that's going to save you a few hundred bucks! :-)

Brett


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