Overview of RAMFS and TMPFS on Linux

3/21/2015 RedHat iTOps: Overview of RAMFS and TMPFS on Linux

http://www.redhat.itopstube.com/2012/02/overview-of-ramfs-and-tmpfs-on-linux.html 1/8

RedHat iTOpsiTOps Home RedHat Basics RHCSA Networking

RedHatiTOps

RedHatiTOpsTube

PopularSearches

MyContent

Tuesday,February21,2012

OverviewofRAMFSandTMPFSonLinux

Usingramfsortmpfsyoucanallocatepartofthephysicalmemorytobeusedasa

iTOpsTubePortal

UbuntuItops

FedoraItops

RedHatItops

MacItops

UnixItops

LinuxITOPS

SUSELinuxItops

DebianiTOps

CoreiTOpsTube

windowsItops

2012(578)

December(7)

June(25)

May(180)

April(300)

February(66)

Feb23(13)

Feb21(16)

WOLWakeonlanGuide:TurnOnServersRemotelyWith...

TheEvolutionandFutureofCommunicationTechnolo...

3StepstoPerformSSHLoginWithoutPasswor

RedHatRecentUpdates

http://www.fedora.itopstube.com/http://www.itopstube.com/javascript:void(0)http://www.redhat.itopstube.com/http://www.redhat.itopstube.com/http://www.windows.itopstube.com/javascript:void(0)javascript:void(0)http://www.unix.itopstube.com/http://www.lijit.com/javascript:void(0)http://www.redhat.itopstube.com/http://www.redhat.itopstube.com/search?updated-min=2012-05-01T00:00:00-07:00&updated-max=2012-06-01T00:00:00-07:00&max-results=50http://www.redhat.itopstube.com/search?updated-min=2012-12-01T00:00:00-08:00&updated-max=2013-01-01T00:00:00-08:00&max-results=7http://www.redhat.itopstube.com/2012/02/evolution-and-future-of-communication.htmlhttp://www.debian.itopstube.com/http://1.bp.blogspot.com/-vfYDHSBDzIc/T0PYMhbxFuI/AAAAAAAAC1w/SWUPh4BNIL8/s1600/image001-722061.jpghttp://www.lijit.com/informer?uri=http%3A%2F%2Fwww.redhat.itopstube.com%2Fhttp://www.mac.itopstube.com/http://www.core.itopstube.com/p/core.htmlhttp://www.redhat.itopstube.com/p/rhcsa.htmljavascript:void(0)http://www.core.itopstube.com/http://www.linux.itopstube.com/http://www.redhat.itopstube.com/search?updated-min=2012-06-01T00:00:00-07:00&updated-max=2012-07-01T00:00:00-07:00&max-results=25javascript:void(0)http://www.suselinux.itopstube.com/http://www.redhat.itopstube.com/2012/02/wol-wakeonlan-guide-turn-on-servers.htmlhttp://www.redhat.itopstube.com/2012/02/3-steps-to-perform-ssh-login-without.htmlhttp://www.ubuntu.itopstube.com/http://itopstube.blogspot.com/p/networking.htmljavascript:void(0)http://www.redhat.itopstube.com/search?updated-min=2012-01-01T00:00:00-08:00&updated-max=2013-01-01T00:00:00-08:00&max-results=50http://www.redhat.itopstube.com/search?updated-min=2012-04-01T00:00:00-07:00&updated-max=2012-05-01T00:00:00-07:00&max-results=50http://www.redhat.itopstube.com/search?updated-min=2012-02-01T00:00:00-08:00&updated-max=2012-03-01T00:00:00-08:00&max-results=50javascript:void(0)http://www.redhat.itopstube.com/2012_02_21_archive.htmlhttp://www.redhat.itopstube.com/2012_02_23_archive.html



partition.Youcanmountthispartitionandstartwritingandreadingfileslikeaharddisk

partition.SinceyoullbereadingandwritingtotheRAM,itwillbefaster.

Whenavitalprocessbecomesdrasticallyslowbecauseofdiskwrites,youcanchoose

eitherramfsortmpfsfilesystemsforwritingfilestotheRAM.

Bothtmpfsandramfsmountwillgiveyouthepoweroffastreadingandwritingfilesfrom

andtotheprimarymemory.Whenyoutestthisonasmallfile,youmaynotseeahuge

difference.Youllnoticethedifferenceonlywhenyouwritelargeamountofdatatoafile

withsomeotherprocessingoverheadsuchasnetwork.

#mkdirp/mnt/tmp

#mountttmpfsosize=20mtmpfs/mnt/tmp

Thelastlineinthefollowingdfkshowstheabovemounted/mnt/tmptmpfsfilesystem.

#dfk

Filesystem1KblocksUsedAvailableUse%Mountedon

/dev/sda23270540050024882604157617%/

/dev/sda11944421856716583611%/boot

1.HowtomountTmpfs

51,307

TotalPageviewsonredhat.itopstube.com

dUsin...

HowToManageDellServersusingOMSA?OpenManage...

OverviewofMySQLinformation_schemaDatabaseWith...

HowToGetHardwareInformationOnLinuxUsingdmi...

OverviewofRAMFSandTMPFSonLinux

HowToMonitorNetworkSwitchandPortsUsingNagi...

IncreaseBugzillaAttachmentSizeUsingMySQLmax_...

http://www.redhat.itopstube.com/2012/02/overview-of-ramfs-and-tmpfs-on-linux.htmlhttp://www.redhat.itopstube.com/2012/02/how-to-manage-dell-servers-using-omsa.htmlhttp://www.redhat.itopstube.com/2012/02/how-to-get-hardware-information-on.htmlhttp://www.redhat.itopstube.com/2012/02/how-to-monitor-network-switch-and-ports.htmlhttp://www.redhat.itopstube.com/2012/02/overview-of-mysql-informationschema.htmlhttp://www.redhat.itopstube.com/2012/02/3-steps-to-perform-ssh-login-without.htmlhttp://www.redhat.itopstube.com/2012/02/increase-bugzilla-attachment-size-using.html



tmpfs51732005173200%/dev/shm

tmpfs204800204800%/mnt/tmp

#mkdirp/mnt/ram

#mounttramfsosize=20mramfs/mnt/ram

Thelastlineinthefollowingmountcommandshowstheabovemounted/mnt/ramramfs

filesystem.

#mount

/dev/sda2on/typeext3(rw)

procon/proctypeproc(rw)

sysfson/systypesysfs(rw)

devptson/dev/ptstypedevpts(rw,gid=5,mode=620)

/dev/sda1on/boottypeext3(rw)

2.HowtomountRamfs

ViewDELLServiceTagandExpressServiceCodeFro...

HowToPerformSSHandSCPWithoutPasswordfromS...

MidnightCommander(mc)Guide:PowerfulTextbased...

HowToUploadDatatoMySQLtablesusingmysqlimpo...

6AwesomeLinuxcdcommandHacksProductivityTi...

Executionsequencefor.bash_profile,.bashrc,.ba...

Oracle11g

http://www.redhat.itopstube.com/2012/02/midnight-commander-mc-guide-powerful.htmlhttp://www.redhat.itopstube.com/2012/02/how-to-upload-data-to-mysql-tables.htmlhttp://www.redhat.itopstube.com/2012/02/oracle-11g-step-by-step-installation.htmlhttp://www.redhat.itopstube.com/2012/02/execution-sequence-for-bashprofile.htmlhttp://www.redhat.itopstube.com/2012/02/6-awesome-linux-cd-command-hacks.htmlhttp://www.redhat.itopstube.com/2012/02/how-to-perform-ssh-and-scp-without.htmlhttp://www.redhat.itopstube.com/2012/02/view-dell-service-tag-and-express.html



tmpfson/dev/shmtypetmpfs(rw)

noneon/proc/sys/fs/binfmt_misctypebinfmt_misc(rw)

sunrpcon/var/lib/nfs/rpc_pipefstyperpc_pipefs(rw)

fusectlon/sys/fs/fuse/connectionstypefusectl(rw)

tmpfson/mnt/tmptypetmpfs(rw,size=20m)

ramfson/mnt/ramtyperamfs(rw,size=20m)

Youcanmountramfsandtmpfsduringboottimebyaddinganentrytothe/etc/fstab.

Primarilybothramfsandtmpfsdoesthesamethingwithfewminordifferences.

Ramfswillgrowdynamically.So,youneedcontroltheprocessthatwritesthedatatomakesureramfsdoesntgoabovetheavailableRAMsizeinthesystem.Letus

sayyouhave2GBofRAMonyoursystemandcreateda1GBramfsandmounted

as/tmp/ram.Whenthetotalsizeofthe/tmp/ramcrosses1GB,youcanstillwritedata

toit.Systemwillnotstopyoufromwritingdatamorethan1GB.However,whenit

goesabovetotalRAMsizeof2GB,thesystemmayhang,asthereisnoplaceinthe

RAMtokeepthedata.

Tmpfswillnotgrowdynamically.Itwouldnotallowyoutowritemorethanthesizeyouvespecifiedwhilemountingthetmpfs.So,youdontneedtoworryabout

controllingtheprocessthatwritesthedatatomakesuretmpfsdoesntgoabovethe

specifiedlimit.ItmaygiveerrorssimilartoNospaceleftondevice.

Tmpfsusesswap.

3.RamfsvsTmpfs

stepbystepInstallationGuidewithSc...

Feb19(17)

Feb14(6)

Feb11(1)

Feb06(13)

2011(515)

http://wiki.linuxquestions.org/wiki/Fstabjavascript:void(0)javascript:void(0)http://www.redhat.itopstube.com/2012_02_06_archive.htmljavascript:void(0)http://www.redhat.itopstube.com/2012/02/oracle-11g-step-by-step-installation.htmlhttp://www.redhat.itopstube.com/2012_02_19_archive.htmlhttp://www.linux.com/feature/121916javascript:void(0)http://www.redhat.itopstube.com/search?updated-min=2011-01-01T00:00:00-08:00&updated-max=2012-01-01T00:00:00-08:00&max-results=50http://www.redhat.itopstube.com/2012_02_11_archive.htmlhttp://www.redhat.itopstube.com/2012_02_14_archive.htmljavascript:void(0)



PostedbyiTOpsTubeat9:45AM

Ramfsdoesnotuseswap.

SincebothramfsandtmpfsiswritingtothesystemRAM,itwouldgetdeletedoncethe

systemgetsrebooted,orcrashed.So,youshouldwriteaprocesstopickupthedata

fromramfs/tmpfstodiskinperiodicintervals.Youcanalsowriteaprocesstowritedown

thedatafromramfs/tmpfstodiskwhilethesystemisshuttingdown.But,thiswillnothelp

youinthetimeofsystemcrash.

Table:Comparisonoframfsandtmpfs

Experimentation Tmpfs Ramfs

FillmaximumspaceandcontinuewritingWilldisplayerrorWillcontinuewriting

FixedSize Yes No

UsesSwap Yes No

VolatileStorage Yes Yes

Ifyouwantyourprocesstowritefaster,optingfortmpfsisabetterchoicewith

precautionsaboutthesystemcrash.

4.DisadvantagesofRamfsandTmpfs

Recommend this on Google

http://www.redhat.itopstube.com/2012/02/overview-of-ramfs-and-tmpfs-on-linux.htmlhttp://www.blogger.com/share-post.g?blogID=4456266953071702743&postID=1959764286767588535&target=emailhttp://www.blogger.com/share-post.g?blogID=4456266953071702743&postID=1959764286767588535&target=pinteresthttp://www.blogger.com/share-post.g?blogID=4456266953071702743&postID=1959764286767588535&target=facebookhttp://www.blogger.com/share-post.g?blogID=4456266953071702743&postID=1959764286767588535&target=bloghttp://www.blogger.com/share-post.g?blogID=4456266953071702743&postID=1959764286767588535&target=twitter

Documents

Overview of RAMFS and TMPFS on Linux