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@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@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@incognito ~]# dmesg |grep Memory Memory: 2054916k/2096896k available (2106k kernel code, 0k reserved, 1299k data, 196k init)
[root@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@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 sharedbuffers 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
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