Software :: Free - Buff - Cache Memory On Debian
Jun 18, 2010What it's the difference between buff(ered) and cache portions of memory?
Code:
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Server :: Like To Understand Linux 'free' Command With Respect To Cache And Free Memory
Mar 27, 2010Was wondering if anyone can explain briefly the relationship of "cache" and free memory in the "free" memory command.
View 2 Replies View RelatedDebian :: High Memory Usage In Cache?
Mar 12, 2011I've installed my debian sid about one month ago (first xfce, next gnome) but noticed that it's kind of really slow. The upgrades take ages, launching (and using) firefox takes so much time,... In comparaison to my ubuntu, archlinux (on the same computer) or previous installation of debian there is clearly a problem somewhere.Today I tried to do a "top" sorted by mem usage : 3.5% xulrunner-stub, 2.1% dropbox, 1.4% aptitude (doing upgrade), 1.4% clementine,... nothing terriblebut still I've 2.7Gb or RAM used (more than 50%)
$ free -m
total used free shared buffers cached
Mem: 3967 26851282 0 79 1938
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Server :: Clear Cache Memory ( RHEL 5.1 ) As It Consumes Almost 100% Physical Memory?
Jan 11, 2010let me know how to clear cache memory ( RHEL 5.1 ) as it consumes almost 100% physical memory.
View 3 Replies View RelatedProgramming :: SHM Memory Counted As Cache Memory With Kernel 2.6.18?
Aug 25, 2010Is that possible that SHM shared memory is counted as cache memory on Linux with kernel 2.6.18?If find it really odd since this memory is not file backed, but I have a piece of code that loads data using shm_open+mmap, and it generates an amount of cache memory in /proc/meminfo that corresponds exactly to the amount of shared memory (I load that data from a file but I am using posix_fadvise(fd,0,0,POSIX_FADV_DONTNEED) to ensure this file is not cached and I made sure that it is working as expected). As far as I know SHM memory was not tagged as cache memory with kernel 2.6.9.If it is the case it is really unfortunate since normally cache memory can be considered to be part of the "available" memory since it can be flushed promptly but this is clearly not the case with SHM memory... Is there an easy way to get the total amount of used SHM memory on a system?
View 4 Replies View RelatedGeneral :: Application Virtual Address Space Memory Allocation - Memory Does Not Get Free
Apr 20, 2010I am using malloc and frees a lot in my program. It shows its allocated but when i remove it doesnt show as the memory is removed(I am using the top command to view VIRT memory usage). If this continously grows what would happen to my program (Will it go out of memory?)
View 4 Replies View RelatedSoftware :: Free Database That Has Low Memory Usage And Innodb And Memory Like Engin
May 3, 2011I am looking for free database that has low memory usage and innodb and memory like engins that has C API and support trigger and client/server support for using in embedded linux systems.
View 8 Replies View RelatedProgramming :: Free-ing Memory - C/C++ - Free()
Jan 29, 2010Here is the code, which just creates a dynamic array? fills it? and prints.
At the end-point? when doing 'free(digits);' I get a debug messge. But the programm continues to work, or it crashes only on free?
How do I need to change the source-code, not to recieve a message from debugger?
Ubuntu :: How To Clean The Cache Memory
Jan 24, 2010I read somewhere that i can clean cache memory with this comand:
Code:
david@lap:~$ sudo echo 3 > /proc/sys/vm/drop_caches
bash: /proc/sys/vm/drop_caches: Permission denied
The problem is that permission is denied as you see...
Ubuntu :: How To Clear The System Cache Memory
Feb 15, 2011Ubuntu 10.10
How do I clear the System cache memory.
For the past few days , I am facing problem in opening websites (firefox & Chrome).
I have to restart the laptop and then access the web sites.
General :: Memory Cache Losing Sync With Disk?
Nov 3, 2010(Ubuntu Linux server, 64-bits)I was troubleshooting a problem with a file (~3.0 GB) which I had just downloaded, but it was failing the integrity test, when I discovered something really unusual.First this is the MD5 of the file after download, which didn't match the expected value:
~% md5sum media.iso
5d74facb904cc1765a468354908a8f34 media.iso
Some time passes, nothing should have changed the file during this time, but when I went to check the file again:
~% md5sum media.iso
a5b97c5016afb39bd67ccfc3fa6ca59e media.iso
This was really unexpected. Since I have a lot of RAM, I suspected this was the effect of caching and something was going awry with it. I decided to retry with the whole file from disk, for my surprise:
~% sudo sysctl -w vm.drop_caches=3 # This linux command invalidates
vm.drop_caches = 3 # everything in the memory cache.
~% md5sum media.iso
2992aa6270f6e1de9154730ed3beedc1 media.iso
I redid it and now it seems to stay consistent, although this still isn't the value I was expecting. Certainly, the contents in memory cache were different from the contents on disk.This is the big problem.To fix the download, I created a torrent on the source machine and opened it in the target machine. Five 1MB chunks out of ~3.0GB failed integrity check. I used the torrent to fix these file chunks and how the file integrity is ok.The problem now is to determine where the data got out-of-sync.
I tested the memory with memtest86+, all but the bit fading test. I was expecting to see some failing memory module, but there wasn't anything. Everything is ok.Filesystem is Ext4, over LVM2, over a 3-disk RAID5 array.Ext4 is considered stable, and if data were inconsistent between disks, mdadm would have warned. But there is nothing in the logs. S.M.A.R.T. error logs are clean, the disks are new (have less than 30 days of "power-on-hours").I'm looking for information about any data-loss bugs in my current kernel (2.6.35), but there doesn't seem to be anything, as far as I looked.what else I could check, or where exactly could be the defect/bug?It is a Ubuntu 10.10 64-bit, Core i7 930, 6 GB non-ECC RAM.
Update: I confirmed that the files are being correctly written to the disk, the pages are being altered after they are read from disk, while in memory. I did a lot more memtests (I left it doing bit fade test overnight),and still nothing. All memory modules seem ok.Some more tests:
~% md5sum media.iso
cc8bcf1ce67ff7704eadc2222650c087 media.iso
~% cp media.iso tmp[code]....(direcat is a version of cat that reads with O_DIRECT, that is, bypassing page cache)There is a clear pattern: it always happens to the 2nd byte in a 16-byte alignment. In that byte, almost always the bit 4 (LSB) flips to one, but there was one instance where bit 2 flipped to zero.
Ubuntu Servers :: Cache Directory And File Structure In Memory?
Aug 11, 2010i am running Ubuntu Lucid x64 as a fileserver that shares its files via SFTP, NFS and Samba. Currently the hard disks are configured to go to standby if they are not needed. This works perfectly as long as no one browses the shares or my HTPC is running: That one repeatedly looks through the shares for new music or movies. In other words my problem is that the disks are spinning up a lot more often than they should have to. Additionally the spin-up time delays the response time while browsing. Since the machine has a lot of unused RAM i want to tell the kernel that it should keep the directory structure in memory. That way the disks would not need to spin up every time someone browses through the directories.
View 2 Replies View RelatedUbuntu :: Natty Clears Memory Cache When Screensaver Launches
May 27, 2011It seems that something is causing the memory cache to be cleared when the screensaver launches. Then when moving the mouse or hitting a key to stop the screensaver it takes forever for the already launched and minimized applications to redisplay. I am using the ubuntu classic desktop.
Now time to rant.
Natty has so many bugs it is impossible to work around them all. This memory issue is one of the worst. The dead zone caused by the static application switcher, and the application switcher plugins for compiz (and probably any override redirect window) is another big one. There is not a single window decorator for compiz that works right. I have encountered two packages with binaries that won't even run (emerald and xpdf). The nvidia drivers seem to have issues (this may be related to this memory clearing issue).
Without a doubt more bugs than any other release of Ubuntu to date. I have worked around most of them by recompiling, and etc., but this is a real pain.
This is all aside from the idiotic switch to unity, when it is clearly not ready for release. The general direction of Ubuntu is really starting to look bad. By the way, what is up with the decision to uglify the desktop with gray scale icons (I know this is an old one, but I haven't really ranted on Ubuntu yet).
Looks like I will have to revert to Maverick.
General :: Crontab To Email When Buffers/cache Memory Reached A Defined Value
Jun 18, 2010I have a Linux server running CentOS with 2GB RAM. I am searching in google and also in this forum but could not find any luck yet. I am searching the way that we can receive notification by system to a specified email when the memory reached a specified value we defined.
Is there any tool or sort of shell script we set via crontab every minute to check that?
General :: What Does Free Memory Mean In Top
Aug 5, 2009I would not exactly consider myself a newbie but this is a bit of a newbie question so here it goes.
When I run top I see used memory and free memory. When I first boot the system there is lots of free memory in about a day or two that memory whittles down from 2GB of Free mem(of 4GB) to 20MB and then maintains 20-50MB of free memory. This seems to be consistent across different servers. At first I thought there had to be some major memory leaks but it just seemed to prevalent to not have been noticed before.
I found a better way to gauge memory usage is the use of the free command. Now I am confused though, what is Free memory as it is defined and monitored in top?
Fedora :: What Programs Can Be Used To Test And Find Faulty Memory (RAM, Video Adapters, Cache)
Oct 23, 2009What programs can be used to test and find faulty memory (RAM, Video adapters, cache)?
View 2 Replies View RelatedSoftware :: Monitoring Tools Which Can Listen Disks / Overhead / Cache / Memory / CPU Performance
Jul 13, 2011I'm searching monitoring tools which can listen disks, overhead, cache, memory, cpu performance.Can anybody help me?
View 4 Replies View RelatedUbuntu :: Memory Is Not Occupied By Any Application But Not Free
Apr 15, 2010I have a very weird memory issue (as you may have guessed from the title). There's a discrepency between the memory accumulated by the various applications (using "ps -eF" to collect that) and the memory reported by system monitor/"free" Basically, I have around 0.5GB of memory that is not occupied by any application, but is not free as well. (It is not used as cache as well)
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Red Hat / Fedora :: Find Actual Free Memory (RAM)?
May 10, 2011When we have Oracle 10g in RedHat, the free memory goes down soon after bootup of the system and never increases. I learnt from various forums that Linux does cache the disk files for the better performance. And when any application requires memory they get the memory and the caching does not block any memory. We want to capture the free memory available for one the harware planning activity.
1) When we use vmstat command, it gives very less free memory. since it caches large size files, the free memory is very low.
2) We tried free command, but how do we know how much actual free memory is available. i.e. excluding the cache usage
Debian Configuration :: What Default Sources.list That Has Free And Non Free Etc For Squeeze
Jun 16, 2010During playing around sources, synaptic playing I messed up the default list. I know I should have been more careful. Anyways could someone tell me what the default the default sources.list that has free and non free etc for squueze please? I have been trying to get the default list but I cannot find it anywhere. There are alot of lists out there but nothing tagged like the "default" list.
View 6 Replies View RelatedGeneral :: How To Free Up Space - Memory Insufficient Error
Apr 25, 2010When I use top to see memory usage, I have 65gb ram but only 1.3gb of it free and remaining is shown as used. When I ran my program It gives memory insufficiency error. Although no other program is using the remaining 63.7gb ram it is hold. How can I get free the unused ram?
View 3 Replies View RelatedGeneral :: Free - Top And Htop Show Different Memory Usage
Jul 12, 2011I'm trying to meter my memory usage. When I use these different programs, they all show me using different amounts of RAM.
View 2 Replies View RelatedGeneral :: Get Free Memory Stat For The Past Few Days?
Jul 5, 2011im trying to collect some data. Is there a way to get the free memory stats over the past few days from some file... i looked into the sar log files but they dont have date stamps in them!
View 6 Replies View RelatedServer :: Free Physical Memory Available Then Why Swap Space Used
Jun 20, 2010Why linux uses swap space, even if there are free physical memory available.
View 4 Replies View RelatedNetworking :: Superuser Will Get Mail System Memory Free Status
Oct 7, 2010The superuser will get a mail about the system memory free status every minute after 9pm?
Which is Correct:
1. * 21 * * * free
2. * 21-0 * * * free
Server :: 100 Percent Swap Usage With Loads Of Free Memory
Dec 10, 2010Nagios had alerted me that the server had a very high load average exceeding the critical level (17+), when logging onto the server I found that all 4GB of the swap was in use despite the fact that there was 15GB+ of free memory (and that's not even including memory from cache and buffers!) Because it seems all heavily used pages were being stored in swap, the I/O wait on the server became very high, and 4 kswapd daemons were taking up nearly 100% available CPU. This did coincide with an error reported by Bacula during a backup job while changing to a bad tape...
From /var/log/bacula.log:
Code:
10-Dec 02:11 bacula-sd JobId 1898: End of medium on Volume "4097" Bytes=434,170,000,000 Blocks=217,084 at 10-Dec-2010 02:11.
10-Dec 02:11 bacula-sd JobId 1898: 3307 Issuing autochanger "unload slot 4097, drive 0" command.
10-Dec 02:12 bacula-sd JobId 1898: 3301 Issuing autochanger "loaded? drive 0" command.
10-Dec 02:12 bacula-sd JobId 1898: 3302 Autochanger "loaded? drive 0", result: nothing loaded.
10-Dec 02:12 bacula-sd JobId 1898: 3304 Issuing autochanger "load slot 4096, drive 0" command.
10-Dec 02:13 bacula-sd JobId 1898: 3305 Autochanger "load slot 4096, drive 0", status is OK.
10-Dec 02:13 bacula-sd JobId 1898: Volume "4096" previously written, moving to end of data.
10-Dec 03:51 bacula-sd JobId 1898: Error: Unable to position to end of data on device "Tape-1" (/dev/IBMtape0n): ERR=dev.c:1384 read e
rror on "Tape-1" (/dev/IBMtape0n). ERR=Input/output error.
10-Dec 03:51 bacula-sd JobId 1898: Marking Volume "4096" in Error in Catalog.
10-Dec 03:51 bacula-sd JobId 1898: 3307 Issuing autochanger "unload slot 4096, drive 0" command.
10-Dec 03:58 bacula-sd JobId 1898: 3301 Issuing autochanger "loaded? drive 0" command.
10-Dec 03:58 bacula-sd JobId 1898: 3302 Autochanger "loaded? drive 0", result: nothing loaded.
10-Dec 03:58 bacula-sd JobId 1898: 3304 Issuing autochanger "load slot 4098, drive 0" command.
10-Dec 03:58 bacula-sd JobId 1898: 3305 Autochanger "load slot 4098, drive 0", status is OK.
10-Dec 03:59 bacula-sd JobId 1898: Wrote label to prelabeled Volume "4098" on device "Tape-1" (/dev/IBMtape0n)
10-Dec 03:59 bacula-sd JobId 1898: New volume "4098" mounted on device "Tape-1" (/dev/IBMtape0n) at 10-Dec-2010 03:59.
At the same time, these messages starting occuring in /var/log/messages:
Code:
Dec 10 03:51:47 07 kernel: Mem-info:
Dec 10 03:51:47 07 kernel: Node 0 DMA per-cpu:
Dec 10 03:51:47 07 kernel: cpu 0 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 0 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 1 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 1 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 2 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 2 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 3 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 3 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 4 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 4 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 5 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 5 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 6 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 6 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 7 hot: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: cpu 7 cold: high 0, batch 1 used:0
Dec 10 03:51:47 07 kernel: Node 0 DMA32 per-cpu:
Dec 10 03:51:47 07 kernel: cpu 0 hot: high 186, batch 31 used:162
Dec 10 03:51:47 07 kernel: cpu 0 cold: high 62, batch 15 used:48
Dec 10 03:51:47 07 kernel: cpu 1 hot: high 186, batch 31 used:0
Dec 10 03:51:47 07 kernel: cpu 1 cold: high 62, batch 15 used:0
Dec 10 03:51:47 07 kernel: cpu 2 hot: high 186, batch 31 used:0
Dec 10 03:51:47 07 kernel: cpu 2 cold: high 62, batch 15 used:0
Dec 10 03:51:47 07 kernel: cpu 3 hot: high 186, batch 31 used:18
Dec 10 03:51:47 07 kernel: cpu 3 cold: high 62, batch 15 used:0
Dec 10 03:51:47 07 kernel: cpu 4 hot: high 186, batch 31 used:159
Dec 10 03:51:47 07 kernel: cpu 4 cold: high 62, batch 15 used:56
...
Dec 10 03:51:47 07 kernel: Node 3 HighMem per-cpu: empty
Dec 10 03:51:47 07 kernel: Free pages: 732052kB (0kB HighMem)
Dec 10 03:51:47 07 kernel: Active:4232128 inactive:3071288 dirty:158210 writeback:0 unstable:0 free:183320 slab:256840 mapped-file:289545 mapped-anon:3805487 pagetables:13063
Dec 10 03:51:47 07 kernel: Node 0 DMA free:10796kB min:4kB low:4kB high:4kB active:0kB inactive:0kB present:10356kB pages_scanned:0 all_unreclaimable? yes
Dec 10 03:51:47 07 kernel: lowmem_reserve[]: 0 3512 9067 9067
Dec 10 03:51:47 07 kernel: Node 0 DMA32 free:213332kB min:2500kB low:3124kB high:3748kB active:1794108kB inactive:1463220kB present:3596296kB pages_scanned:64 all_unreclaimable? no
Dec 10 03:51:47 07 kernel: lowmem_reserve[]: 0 0 5555 5555
Dec 10 03:51:47 07 kernel: Node 0 Normal free:41028kB min:3952kB low:4940kB high:5928kB active:3409444kB inactive:1471120kB present:5688320kB pages_scanned:0 all_unreclaimable? no
Dec 10 03:51:47 07 kernel: lowmem_reserve[]: 0 0 0 0
Dec 10 03:51:47 07 kernel: Node 0 HighMem free:0kB min:128kB low:128kB high:128kB active:0kB inactive:0kB present:0kB pages_scanned:0 all_unreclaimable? no
Dec 10 03:51:47 07 kernel: lowmem_reserve[]: 0 0 0 0
Dec 10 03:51:47 07 kernel: Node 1 DMA free:0kB min:0kB low:0kB high:0kB active:0kB inactive:0kB present:0kB pages_scanned:0 all_unreclaimable? no
...
Well to cut a long story short, I fixed the problem by disabling the swap partition with 'swapoff'. After about 30 mins all the swap was freed and the server went back to normal. I don't dare reactivate the swap partition and unfortunately as this is a live server which currently has no fail over, I can't reboot either
Server Spec:
4 * Dual-Core AMD Opteron(tm) Processor 8214
32GB DDR2 ECC RAM
RHEL 5.5, 2.6.18-194.11.3.el5 SMP x86_64
Running many KVM VMs (All CentOS x64) and kksmd is used.
bacula-dir Version: 5.0.0
IBM Tape Drive using lin_tape module version 1.34.0 according to modinfo
And before anybody asks
# sysctl vm.swappiness
vm.swappiness = 10
Software :: OPENNMS - Can Monitor Disk Space And Free Memory
Jul 16, 2011i had configured the opennms but i didint able to get the disk space and memory alert by mail... and also i need a plgin gor opennms can u tell me wat plugins suit for opennmms monitoring tool ...
View 2 Replies View RelatedProgramming :: Quick Measurement Of Free System Memory From Within C Program
Jul 21, 2010I need to monitor the amount of free physical memory on Linux from within a large C program. The sampling will occur very frequently, so the measurement cannot be performance intensive. The fact that Linux uses much of the theoretically free memory for cache and buffers means that just measuring the free pages is not sufficient. Using free + cache + buffers gives an overestimate as not all cache/buffers can be freed, but I could get a rough idea of how much generally can't and subtract that from the answer.
Possible options that I've come across so far are: Parsing /proc/meminfo - but that involves reading from file which is slow. Extracting the free, cache and buffers values from the output of the Free command - but is there a quick way to do this? Parsing the /proc/freemem file produced by the API here - but this is again reading from file. Is there a way to get that output directly? Speed is an extremely high priority, and the answer it must accurately represent the amount of memory that my program could expand into (to within a few Mb).
CentOS 5 :: Xmlrpc-c Server Free String Memory Alloc-ed By Xmlrpc_parse_value
Feb 24, 2010I have the following function on my xmlrpc server side.
The registration of this function is done as follows from the main function:
The above function makes the server segfault some where on the return path and client gets the response:
Here is what GDB shows when server segfaults....
However if I remove the line "xmlrpc_strfree (node_name);" then server does not segfault and client receives the response correctly. In the xmlrpc-c code it clearly says " Return the string in newly malloc'ed storage that Caller must free." in xmlrpc_data.c::xmlrpc_read_string() which is the function that gets called from xmlrpc_parse_value().
General :: Windows - Free Up Memory "fully Hibernating" A Process?
May 25, 2011Similar to this: How to "hibernate a process" under Linux/Windows? Are there any methods to hibernate a process in a way that it doesn't stay in memory? E.g.: If I don't want to use Firefox, and don't want to close the process of it, and I need free memory, then how can I really hibernate the process so the memory reserved by Firefox is freed up? I need solution for both Windows and Linux!
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