Differential D18541 Diff 51966 head/usr.bin/fortune/datfiles/freebsd-tips

Changeset View

Standalone View

head/usr.bin/fortune/datfiles/freebsd-tips

Context not available.
	command name.	command name.
	-- Dru <genesis@istar.ca>	-- Dru <genesis@istar.ca>
	%	%
	To see how much disk space is left on your partitions, use	To see how much disk space is left on your UFS partitions, use

	df -h	df -h
	-- Dru <genesis@istar.ca>	-- Dru <genesis@istar.ca>
	%	%
	To see the 10 largest files on a directory or partition, use	To see the 10 largest files on a directory or UFS partition, use
		rgrimesUnsubmitted Not Done Inline Actions This reads poorly, better would be: To see the 10 largest files IN a directory or ON a UFS partition, use rgrimes: This reads poorly, better would be: To see the 10 largest files IN a directory or ON a UFS…

	du -h /partition_or_directory_name \| sort -rh \| head	du -h /partition_or_directory_name \| sort -rh \| head
	-- Dru <genesis@istar.ca>	-- Dru <genesis@istar.ca>
Context not available.

	-- Lars Engels <lme@FreeBSD.org>	-- Lars Engels <lme@FreeBSD.org>
	%	%
	You can upload the dmesg of your system to help developers get an overview of commonly used hardware and peripherals for FreeBSD.	You can upload the dmesg of your system to help developers get an overview of commonly
	Use the curl package to upload it in one command:	used hardware and peripherals for FreeBSD. Use the curl package to upload it like this:
	curl -v -d "nickname=$USER" -d "description=FreeBSD/$(uname -m) on \	curl -v -d "nickname=$USER" -d "description=FreeBSD/$(uname -m) on \
	$(kenv smbios.system.maker) $(kenv smbios.system.product)" -d "do=addd" \	$(kenv smbios.system.maker) $(kenv smbios.system.product)" -d "do=addd" \
	--data-urlencode 'dmesg@/var/run/dmesg.boot' http://dmesgd.nycbug.org/index.cgi	--data-urlencode 'dmesg@/var/run/dmesg.boot' http://dmesgd.nycbug.org/index.cgi
	%	%
		Want to know how much memory (in bytes) your machine has available? Let
		sysctl(8) tell you with the following command:

		sysctl hw.physmem
		rgrimesUnsubmitted Not Done Inline Actions Not sure that available is the proper description for this item. Some of that memory is probably "in use" and not available :-) There is also hw.realmem which is the installed memory in the machine. I do get that we call this avail memory in the boot time messages, as that is the available memory for the system after kernel and boot time module loading. Some may interpret this as how to get the free memory right now, and that is not this sysctl. rgrimes: Not sure that available is the proper description for this item. Some of that memory is…

		The number of available CPUs is displayed using this command:
		allanjudeUnsubmitted Not Done Inline Actions this is CPU threads, not necessarily real cores, not sure how best to communicate that succinctly allanjude: this is CPU threads, not necessarily real cores, not sure how best to communicate that…
		bcrAuthorUnsubmitted Done Inline Actions How about using the "sysctl -d" description: Number of active CPUs ? bcr: How about using the "sysctl -d" description: Number of active CPUs ?

		sysctl hw.ncpu

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		When using ZFS as the file system the "df" command will display inaccurate
		allanjudeUnsubmitted Not Done Inline Actions They are not necessarily inaccurate, as just confusing. As the 'size' of the disk keeps shrinking as you write to it, rather than it 'fulling up', but the current wording is probably fine. allanjude: They are not necessarily inaccurate, as just confusing. As the 'size' of the disk keeps…
		bcrAuthorUnsubmitted Done Inline Actions OK, I can change it to "confusing" instead of inaccurate. bcr: OK, I can change it to "confusing" instead of inaccurate.
		rgrimesUnsubmitted Not Done Inline Actions Can we find a way to accurate describe what it is that df is displaying? rgrimes: Can we find a way to accurate describe what it is that df is displaying?
		values. Use the built-in "zfs list" command to get an overview of space usage:

		zfs list -o space

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		To learn more about what your system is doing, take a look at systat(1). For
		example, to get an overview of I/O happening in the system, run:

		systat -iostat
		rgrimesUnsubmitted Not Done Inline Actions systat -vmstat is the much more normal useful display, I would of lead with that here. rgrimes: systat -vmstat is the much more normal useful display, I would of lead with that here.

		Other values are icmp, icmp6, ifstat, ip, ip6, netstat, pigs, sctp, swap, tcp,
		vmstat, or zarc. You can switch between displays using :<display> and exit
		back to your shell, enter

		:quit

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		To set a quota of 10 GB for the user named foo on a ZFS dataset, run the
		following command:

		# zfs set userquota@foo=10G pool/home/foo

		The zfs userspace command can display the quota and current space usage:

		# zfs userspace pool/home/foo

		To unset a quota, assign "none" as the value.
		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		ZFS can save a lot of disk space for log files, much more than the default
		compression algorithm used in newsyslog(8). When you have /var/log on an
		LZ4 compressed dataset, run the following to remove the default compression from newsyslog.conf:

		# sed -i newsyslog.bak s/J// /etc/newsyslog.conf
		allanjudeUnsubmitted Not Done Inline Actions this sed seems a bit risky, you might be able to constrain it to lines that END in J? allanjude: this sed seems a bit risky, you might be able to constrain it to lines that END in J?
		bcrAuthorUnsubmitted Done Inline Actions Yes, I had the same concerns. I look into a more precise solution that targets the end of each line. bcr: Yes, I had the same concerns. I look into a more precise solution that targets the end of each…

		Restart the newsyslog(8) service to make these changes take effect:
		allanjudeUnsubmitted Not Done Inline Actions newsyslog does not run as a service, it is run each hour from /etc/crontab allanjude: newsyslog does not run as a service, it is run each hour from /etc/crontab
		bcrAuthorUnsubmitted Done Inline Actions That's true, although there is a service listed when I do: service -e \| grep newsyslog But there is no such entry in /etc/rc.conf or /etc/rc.conf.local The service method works right away, rather than waiting for the next crontab invocation. That's why I was using it. bcr: That's true, although there is a service listed when I do: service -e \| grep newsyslog But…

		# service newsyslog restart

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		ZFS can display I/O statistics for a given pool using the iostat subcommand.
		By default, it will display one line of current activity. To display stats
		every 5 seconds run the following command (cancel with CTRL+C):

		zpool iostat 5

		To view individual disk activities, specify the -v parameter:

		zpool iostat -v

		Of course, both can be combined. For more options, see zpool(8).
		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		FreeBSD's top(1) utility displays CPU statistics by default.
		To display I/O activity for each process instead, run top like this:

		top -m io

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		ZFS keeps a history of commands run against a specific pool using the
		history subcommand to zpool:

		zpool history

		More details are available using the -i and -l parameters. Note that ZFS
		will not keep the complete pool history forever and will remove older
		events in favor of never ones.
		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		To display the compression ratio for the ZFS dataset /var/log on the pool
		mypool, run the following command:

		zfs get refcompressratio mypool/var/log

		The refcompressratio will only display the compression ratio for that specific
		dataset, not the descendant datasets. To include the child datasets, the
		command looks like this:

		zfs get compressratio mypool/var

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		You can limit the depth of the displayed datasets in the "zfs list" output
		using the -d parameter. To display only the first level of datasets below
		mypool/usr and not the ones deeper than those, run this command:

		zfs list -d 1 mypool/usr

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		The "zfs list" command can be filtered in multiple ways. To display just
		the dataset name, use the -o parameter:

		zfs list -o name mypool/usr

		More columns and their order can be defined by separating them with commas:

		zfs list -o mountpoint,name,avail

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		The output of "zfs list" can be sorted by a specific column using -s. To
		sort the datasets by the "used" column in ascending order, run this command:

		zfs list -s used

		To sort in descending order instead, use -S:

		zfs list -S used

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		To make the "zfs list" output more script-friendly, you can suppress the
		output of the headers for each column by passing the -H parameter:

		zfs list -H

		Another helpful option for script writers is -p, which displays the numbers
		in non-rounded, exact values:
		rgrimesUnsubmitted Not Done Inline Actions examples should put options in alpha order unless they have positional parameters. I am only mentioning this once, it appears all over in this and most manpage examples, but it is a nice consitency to have rgrimes: examples should put options in alpha order unless they have positional parameters. I am only…

		zfs list -p

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		Before deleting a dataset or snapshot, perform a dry run using the -n
		parameter. This is to make sure you really want to delete just that
		dataset/snapshot and not any dependent ones. ZFS will display the resulting
		action when -n is combined with the -v option without actually performing
		it:

		zfs destroy -rvn mypool@mysnap

		Once you are sure this is exactly what you intend to do, remove the -n
		parameter to execute the destroy operation.
		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		To set a custom ZFS property on the mypool pool, you need to provide it
		using the "key1:key2=value" syntax, where the colon (:) is used as the
		separator and identifier from the built-in ZFS properties:

		# zfs set warranty:expires=01.08.2025 mypool

		The custom property is applied to all datasets and can be queried like any
		built-in properties using zfs get:

		zfs get warranty:expires mypool

		To reset the value of a custom property, use the inherit subcommand:

		# zfs inherit warranty:expires mypool

		Removing a custom property from a pool is done using the -r flag to the
		"zfs inherit" command:

		# zfs inherit -r warranty:expires mypool

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		To delete a range of ZFS snapshots, use the % (percent) character after the
		full path to the first snapshot that should be included. For example, to
		simulate deleting snapshots a through (including) d, use this command:

		# zfs destroy -rvn mypool/tmp@a%d

		Once you are sure that this is what you want, remove the -n option:

		# zfs destroy -rv mypool/tmp@a%d
		allanjudeUnsubmitted Not Done Inline Actions Not sure if it is worth doing the other examples: snapshot@%d deletes d and all earlier snapshots snapshot@a% deletes a and all later snapshots snapshot@% deletes ALL snapshots allanjude: Not sure if it is worth doing the other examples: snapshot@%d deletes d and all earlier…
		bcrAuthorUnsubmitted Done Inline Actions Those are good examples worth mentioning (with the proper caution). I'll see if I can add them to this or create a separate one. bcr: Those are good examples worth mentioning (with the proper caution). I'll see if I can add them…

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		You can prevent the removal of a ZFS snapshot by using the hold subcommand.
		For example, to prevent the snapshot called milestone from deletion, run the
		following command:

		# zfs hold milestone_hold mypool/projects@my_milestone

		The "zfs holds" command will list all current snapshots that are protected
		this way (-r for a recursive list):

		# zfs holds -r mypool

		The TIMESTAMP column in the output of the above command is from when the
		hold was created, not the snapshot it holds. The "zfs destroy" command will
		echo a "dataset is busy" message on the console when it encounters a hold.
		Use "zfs release" to release the hold on the snapshot:

		# zfs release milestone_hold mypool/projects@my_milestone

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		A user "sender" needs the following permissions set to send a ZFS dataset:

		# zfs allow -u sender send,snapshot txpool

		On the receiving side, the user "receiver" requires these permissions:

		# zfs allow -u receiver compression,mountpoint,mount,create,receive rxpool

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
		Don't let your zpool fill up completely by creating a dataset with
		reservation.

		# zfs create -o refreservation=<5% of total pool space> <poolname>/reserved

		You can always shrink the reserve if you need the space, but your pool will
		always have space left this way.

		-- Benedict Reuschling <bcr@FreeBSD.org>
		%
Context not available.