Showlock

[Brian K. White]

On 6/18/2013 1:32 PM, Richard Kreiss wrote:
>
>
>> -----Original Message-----
>> From: Dennis Malen [mailto:dmalen at malen.com]
>> Sent: Tuesday, June 18, 2013 12:15 PM
>> To: Richard Kreiss; ken_wakeman at me.com; 'Kenneth Brody'
>> Cc: 'FilePro Mailing List'
>> Subject: RE: Showlock
>>
>> Top Post
>>
>> Still not clear.
>
> Dennis,
>
> Fp, in the days of smaller drives, allowed for adding key/data extents to the same or different drives.  Today with the larger drive capacity, the only time one would want to do this is when the file size is nearing the 2GB limit on a 32bit OS.
>
> I don't recall exactly what the naming convention is for these extents.

To add extents:

# touch keyqualxn dataqualxn
# chown filepro key* data *
# chmod 600 key* data*
(chmod and chown must be run *in this order*, or, just run a recent 
version of setperms instead of chmod & chown)

Where qual is a qualifier (including nothing for unqualified),
and n may be anything from 1 to at least 9. I don't know if they can go 
beyond 9. I think it must start at 1 and count up with no breaks if you 
need more than one extent. IE, if you have one extent it must be x1. If 
you have 2 extents they must be x1 and x2, etc. Each extent adds another 
2G (or whatever your OS/filesystem/fp binary max file size is) to the 
available "file size" to the filepro file, up to the record limit in 
filepro which I don't remember, but @rn are 9,.0 edit.

So, for unqualified with only one extent:

keyx1 datax1

For 3 extents in qualifier foo:

keyfoox1 keyfoox2 keyfoox3 datafoox1 datafoox2 datafoox3

Yes this means there is ambiguity between unqualified with extents, and 
qualifiers that happen to be named x1 - x9. So the first extent of 
unqualifed key is "keyx1", and the regular key in qualifier x1 is also 
"keyx1".
All I can say about that is either try it and see what fp does, or 
"don't do that" meaning don't make any qualifiers named x1, x2, ... x9.

I don't remember if you have to do indexes too and I never use blob or 
memo but I imagine that blob and memo at least must also be extendable 
by the same rules.



The limit per individual file is not simply 2G on 32bit OS. There are at 
least 3 possible things that impose a limit, the OS, the filesystem, and 
the fp binaries.

You could for instance have an OS that can do 64bit file i/o, and fp 
binaries that can do 64bit file i/o, Meaning both could handle file 
sizes in the terabytes, but if you are writing to a fat32 filesystem, 
then the max file size is 4G because that is the limit in fat32.
There are also filesystem-specific tuning/layout options that affect max 
file size where if you have an ext3 filesystem with 1k block sizes, your 
max file size is 16 GB, but if you have a ext3 filesystem with 4k block 
sizes, your max file size is 2 TB. The max file size in various 64bit 
filesystems ranges from as little as 16 GB all the way to 8 EB

Generally though:
older 32bit OS & binaries = 2G
newer linux 32bit os & binaries can do 64bit file i/o = 2TB or more
old or new, 64bit any os & binaries = 2 TB or more

You could also be using old 32bit fp binaries on an otherwise 64bit OS 
and filesystem, and in that case the limit would be 2G, unless the 
binaries are 32bit but new enough to support 64bit file i/o.

You are on AIX? your max file size depends on the same things as above 
but for aix. 32 or 64 bit kernel? what filesystem? And possibly on 
options chosen at the time the filesystem was created, which we can not 
know. For JFS2 it looks like even for a 32bit kernel 1 TB is a safe bet 
for max file size.

http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.baseadmn/doc/baseadmndita/fs_size_limit.htm

-- 
bkw