Getting zRR_DONT_UPDATE_ACCESS_TIME style file opens via
LibC

Hi,

Using NSS primatives to open files, like zOpen, you can specify 
zRR_DONT_UPDATE_ACCESS_TIME to prevent file metadata from being updated 
during file open / read.   Is there a way to do this with sopen / fopen 
or any of the methods available to LibC / CLIB?  Just setting this bit 
during sopen, for example, doesn't seem to be passed down the chain. 
Or is there some other way to achieve the same ( NSS or LibC options, 
SET commands, etc? )

Thanks!

-- Bob

- - - - - - - - - - - - - - - - -
       Robert Charles Mahar
Traffic Shaping Engine for NetWare
    http://www.TrafficShaper.com

Robert Charles Mahar пишет:
> Hi,
> 
> Using NSS primatives to open files, like zOpen, you can specify 
> zRR_DONT_UPDATE_ACCESS_TIME to prevent file metadata from being updated 
> during file open / read.   Is there a way to do this with sopen / fopen 
> or any of the methods available to LibC / CLIB?  Just setting this bit 
> during sopen, for example, doesn't seem to be passed down the chain. Or 
> is there some other way to achieve the same ( NSS or LibC options, SET 
> commands, etc? )

Hello,

In CLIB, I did this using stat()/ChangeDirectoryEntry() with 
MLastAccessedDateBit.

With best wishes

Hi,

The problem I'm trying to avoid is ATIME meta-data updates to NSS which 
cause a limit on the number of files one can open / read per second as 
it blocks and waits around for solid I/O to happens for the NSS data 
strictures.  So its not an issue of preservation of ATIME info. 
Changing the access time back to the prior value would cause the same 
issue x 2 as NSS would update the value and we would reset it.

( Or perhaps I'm missing the gist of what you are proposing. )

-- Bob

- - - - - - - - - - - - - - - - -
       Robert Charles Mahar
Traffic Shaping Engine for NetWare
    http://www.TrafficShaper.com
- - - - - - - - - - - - - - - - -


Dmitry Mityugov wrote:
> Robert Charles Mahar пишет:
>> Hi,
>>
>> Using NSS primatives to open files, like zOpen, you can specify 
>> zRR_DONT_UPDATE_ACCESS_TIME to prevent file metadata from being 
>> updated during file open / read.   Is there a way to do this with 
>> sopen / fopen or any of the methods available to LibC / CLIB?  Just 
>> setting this bit during sopen, for example, doesn't seem to be passed 
>> down the chain. Or is there some other way to achieve the same ( NSS 
>> or LibC options, SET commands, etc? )
> 
> Hello,
> 
> In CLIB, I did this using stat()/ChangeDirectoryEntry() with 
> MLastAccessedDateBit.
> 
> With best wishes
> 

Robert Charles Mahar пишет:
> Hi,
> 
> The problem I'm trying to avoid is ATIME meta-data updates to NSS which 
> cause a limit on the number of files one can open / read per second as 
> it blocks and waits around for solid I/O to happens for the NSS data 
> strictures.  So its not an issue of preservation of ATIME info. Changing 
> the access time back to the prior value would cause the same issue x 2 
> as NSS would update the value and we would reset it.
> 
> ( Or perhaps I'm missing the gist of what you are proposing. )

No, you are correct, that would just double the number of updates.

And zRR_DONT_UPDATE_ACCESS_TIME, according to the old copy of 
fs64_enu.pdf that I have, is not implemented.

With best wishes

Yeah, I saw that too, but I thiugh I saw in the NSS rev history that 
these were made to function properly.  Irrespective of the docs, it 
seems like its implemented as when I use zOpen on 6.5.7 it does, in 
fact, seem to work as expected.  Now if that's what Novell intended, I 
don't know. :-)  But I think

It would seem like an astoundingly easy change for Novell to implement a 
Linux style noatime set parameter for NSS on NetWare.   As I'd imagine 
the places where this happens are pretty well defined and easy to short 
circuit.

-- Bob

- - - - - - - - - - - - - - - - -
       Robert Charles Mahar
Traffic Shaping Engine for NetWare
    http://www.TrafficShaper.com
- - - - - - - - - - - - - - - - -


Dmitry Mityugov wrote:
> Robert Charles Mahar пишет:
>> Hi,
>>
>> The problem I'm trying to avoid is ATIME meta-data updates to NSS 
>> which cause a limit on the number of files one can open / read per 
>> second as it blocks and waits around for solid I/O to happens for the 
>> NSS data strictures.  So its not an issue of preservation of ATIME 
>> info. Changing the access time back to the prior value would cause the

>> same issue x 2 as NSS would update the value and we would reset it.
>>
>> ( Or perhaps I'm missing the gist of what you are proposing. )
> 
> No, you are correct, that would just double the number of updates.
> 
> And zRR_DONT_UPDATE_ACCESS_TIME, according to the old copy of 
> fs64_enu.pdf that I have, is not implemented.
> 
> With best wishes
>