Interesting. I wonder if it has something to do with the chipset the motherboard is using? Here's free on a new server of mine, with 16gb, runing x86_64, centos 4.4 [root at vmhost ~]# free -m total used free shared buffers cached Mem: 16029 16004 24 0 2144 13002 -/+ buffers/cache: 858 15171 Swap: 1983 0 1983 [root at vmhost ~]# dmesg |grep Memory Memory: 16413932k/17563648k available (2106k kernel code, 0k reserved, 1299k data, 196k init) I see the same thing you do, basiclly a gigabyte is "missing" However, on a machine with only 2g of ram, less ram is 'missing': [root at incognito ~]# dmesg |grep Memory Memory: 2054916k/2096896k available (2106k kernel code, 0k reserved, 1299k data, 196k init) [root at incognito ~]# free -m total used free shared buffers cached Mem: 2007 1988 18 0 31 1827 -/+ buffers/cache: 129 1877 Swap: 996 0 995 Both these boxes are brand new Dells, first one's a 2950, the other an 860. Gordon On 3/5/07, Kanwar Ranbir Sandhu <m3freak at thesandhufamily.ca> wrote: > Hi Everyone, > > My server is only seeing 4.8 GB out of 6 GB available. I don't know > why. > > I have a CentOS 4.4 x86_64 server running on a Tyan s2895 with 6 GB of > RAM (two 1 GB sticks and 2 2 GB sticks). I upgraded the RAM, powered up > the server, and when CentOS was finished booting, checked the available > RAM with free. This is what it's reporting: > > total used free shared > buffers cached > Mem: 4809064 4769492 39572 0 197156 > 3127704 > -/+ buffers/cache: 1444632 3364432 > Swap: 2064376 176 2064200 > > The BIOS sees all of the RAM. In fact, it looks to me like the kernel > knows 6 GB is available. But, it is only using 4.8 GB because I see > this in dmesg: > > Memory: 4808464k/6291456k available (2106k kernel code, 0k reserved, > 1299k data, 196k init) > > What happened to the other 1 GB+ of RAM? > > BTW, the server isn't running all the newest updates, but it is running > the latest CentOS 4 kernel (2.6.9-42.0.10.ELsmp). > > Regards, > > Ranbir > -- > Kanwar Ranbir Sandhu > Linux 2.6.19-1.2911.fc6 i686 GNU/Linux > 11:39:08 up 2 days, 10:28, 2 users, load average: 1.18, 0.64, 0.60 > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >