The reason we did not use 64 bits O.S. due to we still have some problem run 64 bit ORACLE on X86_64. I have another question: since server we have is "SMP" how come it can show 32 GB RAM on application like "top" and "free"? Thanks. --- 09/3/30 (一)，John R Pierce <pierce at hogranch.com> 寫道： > 寄件者: John R Pierce <pierce at hogranch.com> > 主旨: Re: [CentOS] How to check server kernel support 32 Gb RAM (X86, > 收件者: centos at centos.org > 日期: 2009 3 30 一 下午 2:24 > > > > > > we have CENTOS 4.7 (X86) on DELL server, I already put > 32 GB RAM on it. I can use "top" or "free" to check > memory and it did show 32 GB. > > > > I check REDHAT site and found it say: > > > > The "SMP" kernel supports a maximum of 16GB of main > memory. Systems with more than 16GB of main memory use the > "Hugemem" kernel. > > > > I use "uname -r" to check kernel and it show: > > > > # uname -r > > 2.6.9-78.0.13.ELsmp > > > > It did NOT show "Hugemem", does this server kernel > support 32 GB or not? If NOT how can I change kernel > to "hugeme"? > > Dare we ask why this isn't a 64bit server? > using 32gb of memory on a processor architecture that can > only directly address 4GB at a time is kind of brutal, > unless this server is handling a rather large number > of connection sessions at the same time. For > instance, a 32bit database server will have a max of about > 2.5GB of shared memory usable. > > to install the hugemem kernel, > yum install kernel-hugemem > reboot, and test this by selecting it in the grub menu, > then adjust /boot/grub.conf to suit. > > read the release notes carefully on hugemem, its a very > high overhead thing, as the kernel runs in a private > memory space seperate from the applications, so all > kernel<->user transfers are complex and slow. > http://www.centos.org/docs/4/html/release-notes/as-x86/ > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > ______________________________________________________________________________________________________ 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ http://tw.mg0.mail.yahoo.com/dc/landing