Many thanks Andrew for the info :-) Best regards,
Kaya On 02/01/10 12:29, andrew wrote: > See comments inline below: > > > >>> You can limit the amount of memory that ZFS uses >>> >> for its cache (the ARC - Adaptive Replacement Cache) >> as described here: >> >>> >>> >> http://www.solarisinternals.com/wiki/index.php/ZFS_Evi >> l_Tuning_Guide#Limiting_the_ARC_Cache >> >>> In fact the live CD does just that in order to >>> >> allow OpenSolaris to install on systems with only >> 512MB memory - check /etc/system while booted from >> the live CD to see what it is set to. >> >>> Cheers >>> >>> Andrew. >>> >>> >> Hi, I do NOT wish to hijack this thread but have a >> question related to this >> answer: >> >> what is the advantage or disadvantage of limited the >> ZFS cache??? >> > Read the page I linked to. > > >> Additionally does it depend on system size; ie. how >> large the - and how >> many hard disks there are?? >> > The *maximum* ARC size is based on the total amount of RAM in the system if I > recall correctly. It will default to 7/8ths of available RAM, or RAM minus 1G > - whichever is greater. It starts of small but gets bigger as more stuff is > read off disk. The ARC is shared between all ZFS pools and filesystems which > you have active on the system - again see the page I linked to for more > details. > > >> So say for a system with 2GB memory if the app + >> kernel + background >> procs takes up 1.5GB then if one limits the ZFS cache >> to 512MB what >> significance does this have?? >> > It means your background processes get less of a hard time from the ARC cache > as they fight for memory, since the ARC will not attempt to grow beyond > 512MB. You will probably want to have a play with it and see what the effect > is on your actual system - it may take a bit of trial and error to get the > right setting for your particular circumstances. > > >> Regards and apologies for the intrusion!! >> > > Not a problem ;-) > > Andrew. > >> Kaya >> _______________________________________________ >> opensolaris-help mailing list >> opensolaris-help at opensolaris.org >>
