How do I change the default options for zfs filesystems on an existing zpool?
The zpool manual tells me how to set such options on creation (note the -O instead of -o to distinguish filesystem options from pool options):
zpool create -O atime=off -O compression=on ...
That way, future filesystem creation commands can be shortened from:
zfs create -o atime=off -o compression=on ...
to:
zfs create ...
However, what if I didn't set the -O on pool creation? How can I set or change them for an existing pool?
You can set them on the top-level dataset in the pool, like this:
zfs set compression=on <name of pool>
After that, all child datasets you create inside that will inherit those properties.
Most properties are propagated to child datasets on creation, so you may have to run it on each pre-created filesystem / zvol manually to make the whole pool have the same properties. You can use the same command for that, just substitute in the dataset name you need to update the property for.
Related
According to the documentation it's possible to add the parameter --defaults-group-suffix to a mysql command, for it to "In addition to the default option groups, also read option groups with the given suffix".
So in case I use:
--defaults-group-suffix=.sample
A mariadb-Server started with this option will read both, the following blocks:
[mariadbd]
…
[mariadbd.sample]
…
So I can put options which should apply to the specific instance to the second block.
My question is: Is there a way to add an option group, which is only evaluated, when the parameter --defaults-group-suffix is not provided, in other words empty?
The default block [mariadbd] obviously can't be used, since it is read by all instances with a defined suffix.
Additional question, since I can't find it in the documentation: If one option is specified multiple times in one (or more) configuration files: Is it the first, or the last match, that applies?
According to the stackoverflow guidelines, next time please only ask one question per posting.
1st question: No, it is not possible - the suffix option is an additional option, there are no conditions which check suffix and other options.
2nd question: If multiple configuration files with same options but different values are used, the option/value from last read configuration file will be used. Check the read order of configuration files by executing
mysqld --help --verbose | grep -C1 "Default options"
Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf ~/.my.cnf
I have a large amount of text files stored on a Red Hat server that contain explicit Windows paths. Today, that path has changed and I would like to change the text files to reflect the new path. As they are Windows paths, they all contain single backslashes. I would like to maintain the single backslashes if possible.
I wanted to ask what the best method to perform this string replacement would be. I have made backups of folders so that I may test on a smaller scale before applying to the larger scale that will affect my group members.
Example:
Change $oldPath to $newPath in all *.py files recursively contained in current directory.
i.e. $oldPath\common\file_referenced should become $newPath\common\file_referenced
Robustly using any awk in any shell on every Unix box and regardless of which characters your old or new directory paths contain and whether or not the final directory in either old or new could be a substring of another existing directory name:
$ cat file
\old\fashioned\common\file_referenced
$ oldPath='\old\fashioned'
$ newPath='\new\fangled\etc'
$ awk '
BEGIN { old=ARGV[1]; new=ARGV[2]; ARGV[1]=ARGV[2]="" }
index($0"\\",old"\\")==1 { $0=new substr($0,length(old)+1) }
1' "$oldPath" "$newPath" file
\new\fangled\etc\common\file_referenced
To update all .py files in a directory you could use GNU awk for -i inplace, or you could do for i in *.py; do awk '...' old new "$i" > tmp && mv tmp "$i"; done, or you could use find and/or xargs, etc. - any of the common Unix ways to process multiple files with any command.
I follow the basically solutions to solve it, but I already had the problem.
In my configure.ac file I have a check for mysql:
AC_CHECK_HEADER([mysql/mysql.h], ,AC_MSG_ERROR([Could not find mysql headers !]))
and of course it complain because, as explain here:
If the header files are installed in a nonstandard location, such as
/opt/include, and CPPFLAGS doesn't refer to that directory-for
example, as -I/opt/include-the AC_CHECK_HEADER macro will fail, even
though the files do exist on the system. However, this is an issue for
the system's administrator. Part of the convenience of autoconf is
that you, as the developer, don't need to worry about these details.
So, as developer, what's the way to go to solve it properly ?
I also put the path of real location in Makefile with -I/usr/include/mysql, but it continues to complain.
EDIT: as suggestd I post the configure.ac (the main parts):
useMysql=no
AC_MSG_CHECKING([whether to use mysql])
AC_ARG_ENABLE(mysql,
[ --enable-mysql Enable mysql support],
[MYSQL="$enableval"]
useMysql=yes,
[MYSQL="no"]
)
AC_MSG_RESULT([$MYSQL])
AC_SUBST([MYSQL])
[...]
if test "$MYSQL" = "yes"; then
AC_CHECKING([for MYSQL Library and Header files])
AC_CHECK_HEADER([mysql/mysql.h], ,AC_MSG_ERROR([Could not find mysql headers !]))
AC_CHECK_LIB(mysqlclient, mysql_init, [ MYSQL_LIBS="-lmysqlclient" ], [AC_MSG_ERROR([$PACKAGE_NAME requires but cannot find mysqlclient])])
AC_DEFINE(USE_MYSQL, 1, [Use MYSQL library])
AC_SUBST(MYSQL_LIBS)
fi
then I use the MYSQL_LIBS in the Makefile:
AM_CFLAGS = -g -fPIC -rdynamic -I$(top_srcdir)/include -I/usr/include/mysql
The OpenGrok wrapper script has an update option, but when I run it without any options (as echoed in the usage), I get
Loading the default instance configuration ...
FATAL ERROR: OpenGrok Source Path /var/opengrok/src doesn't exist - Aborting!
I have also tried specifying the SRC_ROOT, but continue to get the same error.
This might not be the right answer, but I have been able to update by re-running the index job itself. It doesn't take as long as the initial indexing.
from https://github.com/OpenGrok/OpenGrok
E.g. if opengrok data directory is /tank/opengrok and source root is
in /tank/source then to get more verbosity run the indexer as:
$ OPENGROK_VERBOSE=true OPENGROK_INSTANCE_BASE=/tank/opengrok \
./OpenGrok index /tank/source
SRC_ROOT is a variable in the OpenGrok wrapper (normally in /usr/opengrok/bin/OpenGrok), this variable is to say OpenGrok where you have your src code to be indexed. So you need to edit it:
SRC_ROOT="your/src/path"
Also, after that maybe you'll se an error for the Data location... and you have to set also the variable DATA_ROOT (index location)
DATA_ROOT="you/data"
Is it possible to specify which .my.cnf file mysql client should use? I have 2 mysql instances running on different ports and want to only need to specify a filename with credentials.
As documented under Command-Line Options that Affect Option-File Handling:
When specifying file names, you should avoid the use of the “~” shell metacharacter because it might not be interpreted as you expect.
--defaults-extra-file=file_name
Read this option file after the global option file but (on Unix) before the user option file. If the file does not exist or is otherwise inaccessible, the program exits with an error. file_name is interpreted relative to the current directory if given as a relative path name rather than a full path name.
--defaults-file=file_name
Use only the given option file. If the file does not exist or is otherwise inaccessible, the program exits with an error. file_name is interpreted relative to the current directory if given as a relative path name rather than a full path name.
--defaults-group-suffix=str
If this option is given, the program reads not only its usual option groups, but also groups with the usual names and a suffix of str. For example, the mysql client normally reads the [client] and [mysql] groups. If the --defaults-group-suffix=_other option is given, mysql also reads the [client_other] and [mysql_other] groups.
Note that "to work properly, each of these options must be given before other options".