[SOLVED] Losing lots of space when formatting as EXT3

[esqobar]

Hello everyone.

I was wondering if anyone could help me with this:

Is it normal to lose 6.5GB (yes, that's Gigabytes) when formatting a drive as EXT3? I have just purchased a Western Digital 'My Passport' 250GB drive to (amongst other things) back up my /home partition.

I have formatted ~100GB as FAT32 for misc uses and the other ~150GB as EXT3 for my backups. Bringing up a properties sheet on the newly partitioned EXT3 partition reveals that ~6.5GB is already used!

I know that file systems take up some space for the allocation table and sometimes reserve more than they are using, but is 6.5GB normal or is something likely wrong with my drive or the way I formatted it (GParted in Ubuntu Hardy)? It just seems a bit excessive to me.

Thanks in anticipation of your expert replies

[Lakshmipathi]

Hi,
Welcome to LF
6.5GB? I think ,there's something went wrong. Can you post the output of command

fdisk -l

so that people here can understand your problem correctly.

[coopstah13]

don't forget that by default 5% of the blocks are reserved for superuser as well

[esqobar]

Thanks for the quick response guys.

Coopstah13, I think that might be the reason. I have since found a post on the Ubuntu forums entitled "Disk capacity, free space, and Ext3 reserved blocks" (I can't link it in until I have made 15 posts on this forum).

I will research it a little more and do the maths when I get home later and post back. I wouldn't have known what to look for if it weren't for your reply so thanks.

[coopstah13]

reserved blocks aren't necessary on non system partitions, its fairly easy to remove them:

sudo tune2fs -m 0 /dev/device

where device is the partition, such as sda1, sdb2, sdc3, etc.

[reed9]

Advertised disk drive space is almost always larger than actual space, even on an unformatted drive as well. 6.5 GB out of an advertised 250 GB seems really good to me.

When a Byte is not a Byte

[esqobar]

Many apologies for not getting back to you guys last night, but an offer of pizza and beer got the better of me.

I haven't checked my drive since, but I'm certain that these reserved blocks are the explanation. Therefore this query can be considered resolved.

Thanks for your help!

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Taken from the mkfs.ext3 - Linux man page:

-m reserved-blocks-percentage

Specify the percentage of the filesystem blocks reserved for the super-user. This avoids fragmentation, and allows root-owned daemons, such as syslogd, to continue to function correctly after non-privileged processes are prevented from writing to the filesystem. The default percentage is 5%.