Oracle RAC - limits.conf, Oracle block
Oracle RAC Solution · Config document · referenced from Operating system preparation
The resource limits of the accounts oracle and grid, added to /etc/security/limits.conf. The guide's minimum values stay in the file as comments; the active lines are higher. The notes show only this added block, not the rest of the file.
| Item | Value |
|---|---|
| Path | /etc/security/limits.conf |
| On | oradb01 and oradb02 |
| Shown here | the block added to the existing file; the notes show ... above it |
| Applied by | pam_limits.so, at the next login of the account; the line session required pam_limits.so was appended to /etc/pam.d/login |
| Operating system | SUSE Linux Enterprise Server 11 SP3 |
The file
# ... (the existing file continues above; the notes do not show it) # Limits (minimum values) for running an Oracle database # oracle soft nproc 2047 # oracle hard nproc 16384 # oracle soft nofile 1024 # oracle hard nofile 65536 # oracle soft as unlimited # oracle hard as unlimited oracle soft nofile 131072 oracle hard nofile 131072 oracle soft nproc 131072 oracle hard nproc 131072 oracle soft as unlimited oracle hard as unlimited oracle soft core unlimited oracle hard core unlimited oracle soft memlock 3500000 oracle hard memlock 3500000 grid soft nofile 131072 grid hard nofile 131072 grid soft nproc 131072 grid hard nproc 131072 grid soft as unlimited grid hard as unlimited grid soft core unlimited grid hard core unlimited grid soft memlock 3500000 grid hard memlock 3500000
| Item | Meaning | Unit |
|---|---|---|
nofile | open file descriptors | count |
nproc | processes of the user | count |
as | address space | KB, here unlimited |
core | size of core files | KB, here unlimited |
memlock | memory that may be locked into RAM | KB; 3500000 KB is a little over 3.3 GiB |
The commented nproc and nofile lines are the values of the installation guide (soft nproc 2047, hard 16384; soft nofile 1024, hard 65536); the commented as lines are not from Oracle's table. The active lines set soft and hard limits to the same value, 131072, for both accounts. memlock matters when the SGA is to be locked or placed in huge pages; it is below the kernel.shmmax of 4124030976 bytes set in sysctl.conf, Oracle block. The notes do not say how 3500000 was chosen, and no huge pages are configured anywhere in them.
The same numbers appear once more in profile.local, which raises the soft limits in the login shell.
Checked against Oracle AI Database 26ai
| As built | Today |
|---|---|
nofile 131072, soft and hard | Recommended range unchanged since 11.2: soft at least 1024, hard at least 65536 |
nproc 131072, soft and hard | Soft at least 2047, hard at least 16384 |
no stack line | Soft at least 10240 KB, hard at least 10240 KB and at most 32768 KB. This was already in the 11.2 table and is missing here |
memlock 3500000 | At least 90 percent of RAM when HugePages are enabled, at least 3145728 KB when they are not. 3500000 KB passes the second rule |
as unlimited, core unlimited | Not in Oracle's table, in 11.2 or in 26ai. Harmless |
pam_limits.so appended to /etc/pam.d/login | The step is not in the 11.2, 19c or 26ai guides; it comes from older ones. On SLES 15 it is redundant: the default common-session already loads pam_limits |
the block in /etc/security/limits.conf | Still read; drop-in files in /etc/security/limits.d/ are the alternative |
The values are still acceptable to a current installer, with the stack lines added. On SLES 15 the installation guide adds a limit that is not in this file at all: DefaultTasksMax=65535 in /etc/systemd/system.conf.