[CentOS] Re: software raid

David A. Woyciesjes david.woyciesjes at yale.edu
Thu Mar 29 19:12:32 UTC 2007

John R Pierce wrote:
>> http://en.wikipedia.org/wiki/FAT32 claims 4GB filesize, and 8TB partition
>> size. the 32GB partition limit is a WinXP-ism to make people use NTFS.
> a 300 Gb fat32 would have either an obscenely large fat table, or an 
> obscenely large cluster size.   if you used 4k clusters, each 'fat' 
> table would be 300 megabytes, this has to be sequentially scanned to 
> calcuate freespace, and it has to be scanned to find free blocks for 
> file and directory allocations.    If you used 32k byte clusters, this 
> would be reduced to 37 megabytes for the FAT, but then even the tiniest 
> files would waste 32 k bytes.
> FAT also has no support for file ownership or access rights.   It has no 
> journaling, so any abnormal events such as unexpected/sudden reboots 
> WILL result in lost freespace (orphaned files/fragments), AND its prone 
> to crosslinking which is very hard to repair.    FAT was designed for 
> floppy disks and hard disks that were a few megabytes back in the early 
> 80s.   It has no way of grouping cluster allocations together, so it has 
> a very strong tendancy to extreme fragmentation, and as the FAT tables 
> are quite large on a filesystem this size, requires frequent extra seeks 
> to locate the next block.   4GB is an absolute limit on size of a single 
> file (so, no DVD ISO images, no large TARs, etc).   Directories are 
> sequentially scanned only, so large directories that spill over a few 
> clusters become excruciatingly slow to even open files from.

	All goo information. I'm probably going to keep Ext3 on the 2 80GB 
server drives, with Ext2IFS loaded on the W2K install of the server.
	Probably have an 80GB FAT32 partition on the external drive. I suppose 
I could also then 2 other 80GB partitions on is also, NTFS and Ext3... 
Anybody confused yet?

	Basically, I don't want to lose anything to a drive crash...

--- David Woyciesjes
--- ITS Help Desk Support Technician
--- Yale University Client Support
--- 100 Church Street South, Suite 214
--- New Haven, CT 06519
--- (203) 785-3200

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