Re: Filesystem and free space
Hi, On 2021-12-13 2:47 a.m., Tom Dial wrote: > > > On 12/12/21 12:28, Teemu Likonen wrote: >> * 2021-12-12 14:13:19-0500, Polyna-Maude Racicot-Summerside wrote: >> >>> How can I ensure that user (or a software being run by a user that >>> goes crazy) doesn't fill up the whole filesystem ? >> Commands mkfs.ext4 and tune2fs have this option: >> >> -m reserved-blocks-percentage >>Set the percentage of the filesystem which may only be >>allocated by privileged processes. Reserving some number of >>filesystem blocks for use by privileged processes is done to >>avoid filesystem fragmentation, and to allow system daemons, >>such as syslogd(8), to continue to function correctly after >>non-privileged processes are prevented from writing to the >>filesystem. Normally, the default percentage of reserved >>blocks is 5%. >> >> See the last sentence. By default normal users can't fill the entire >> space. Use tune2fs to change options for an existing file system. > > In addition, per user and per group file system quotas have been available in > Unix and Linux for as long as I can remember. For Debian, see > https://debian-handbook.info/browse/stable/sect.quotas.html. Man pages for > mkfs.ext4, tune2fs, and edquota (and probably others) have additional > relevant information. > Original post : Now here's my question : How can I ensure that user (or a software being run by a user that goes crazy) doesn't fill up the whole filesystem ? I know there's quota but what I want to ensure is simply that no user can write to disk unless there's at least 2 GB left free on partition. Is this possible ? > Regards, > Tom Dial > >> >> -- /// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/ // OpenPGP: >> 6965F03973F0D4CA22B9410F0F2CAE0E07608462 > > -- Polyna-Maude R.-Summerside -Be smart, Be wise, Support opensource development OpenPGP_signature Description: OpenPGP digital signature
Re: Filesystem and free space
On Sun, Dec 12, 2021 at 02:13:19PM -0500, Polyna-Maude Racicot-Summerside wrote: I know there's quota but what I want to ensure is simply that no user can write to disk unless there's at least 2 GB left free on partition. Is this possible ? As another has mentioned, there's reserved-blocks-percentage at filesystem creation time, but it only distinguishes between superuser and not-superuser. But you could set the % such that the reserved space was 2GiB that way. Personally, I leave the reserved block quota at the default (which means I can always do some basic things as root) and for the filesystems which need reserved space to operate, I create an empty non-sparse file of the appropriate size: ▶ stat /mnt/emergencySpace File: /mnt/emergencySpace Size: 1073741824 Blocks: 2097152IO Block: 4096 regular file If/when the filesystem fills up such that the operations that need space fail, I can quickly remove the emergencySpace file, run those operations, and then do a deeper clean-up (removed old backup increments, or whatever has caused the fill-up). -- Please do not CC me for listmail. Jonathan Dowland ✎j...@debian.org https://jmtd.net
Re: Filesystem and free space
On 12/12/21 12:28, Teemu Likonen wrote: > * 2021-12-12 14:13:19-0500, Polyna-Maude Racicot-Summerside wrote: > >> How can I ensure that user (or a software being run by a user that >> goes crazy) doesn't fill up the whole filesystem ? > Commands mkfs.ext4 and tune2fs have this option: > > -m reserved-blocks-percentage >Set the percentage of the filesystem which may only be >allocated by privileged processes. Reserving some number of >filesystem blocks for use by privileged processes is done to >avoid filesystem fragmentation, and to allow system daemons, >such as syslogd(8), to continue to function correctly after >non-privileged processes are prevented from writing to the >filesystem. Normally, the default percentage of reserved >blocks is 5%. > > See the last sentence. By default normal users can't fill the entire > space. Use tune2fs to change options for an existing file system. In addition, per user and per group file system quotas have been available in Unix and Linux for as long as I can remember. For Debian, see https://debian-handbook.info/browse/stable/sect.quotas.html. Man pages for mkfs.ext4, tune2fs, and edquota (and probably others) have additional relevant information. Regards, Tom Dial > > -- /// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/ // OpenPGP: > 6965F03973F0D4CA22B9410F0F2CAE0E07608462
Re: Filesystem and free space
* 2021-12-12 14:13:19-0500, Polyna-Maude Racicot-Summerside wrote: > How can I ensure that user (or a software being run by a user that > goes crazy) doesn't fill up the whole filesystem ? Commands mkfs.ext4 and tune2fs have this option: -m reserved-blocks-percentage Set the percentage of the filesystem which may only be allocated by privileged processes. Reserving some number of filesystem blocks for use by privileged processes is done to avoid filesystem fragmentation, and to allow system daemons, such as syslogd(8), to continue to function correctly after non-privileged processes are prevented from writing to the filesystem. Normally, the default percentage of reserved blocks is 5%. See the last sentence. By default normal users can't fill the entire space. Use tune2fs to change options for an existing file system. -- /// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/ // OpenPGP: 6965F03973F0D4CA22B9410F0F2CAE0E07608462 signature.asc Description: PGP signature
Filesystem and free space
Hi, I've learned thru this mailing list that it was something "from decades ago" to create a filesystem for /tmp, /var, /home, /usr, etc unless really needed. I must admit it make sense and I'd be better served by either a one partition or only a /home separate. Now here's my question : How can I ensure that user (or a software being run by a user that goes crazy) doesn't fill up the whole filesystem ? I know there's quota but what I want to ensure is simply that no user can write to disk unless there's at least 2 GB left free on partition. Is this possible ? Thanks And happy new years / Christmas / whatever you do take some time off. -- Polyna-Maude R.-Summerside -Be smart, Be wise, Support opensource development OpenPGP_signature Description: OpenPGP digital signature
