RAM for older machines like I use is fairly cheap these days. But flash memory is just as cheap or cheaper. So I'd like to ask about the feasibility of expanding my system's memory using flash memory. And about whether creating a partition for swap on the flash memory, or whether a swap file on the flash device, is the better way to go.
By flash memory I have in mind mainly USB sticks or what are sometimes called "pen drives." But I do also have CF and SD cards that, with the proper cheap adapter (one of which I already own for adapting CF) could be used to create extra swap space. So, what is the current consensus on the feasibility/advisability of using flash memory for swap? I've read about the limited write cycles of flash being an argument against using it for swap. But recent reading indicates to me that the limited write cycles problem applies mostly to older, smaller-capacity flash memory. Some will come out and say that, for larger-capacity flash memory, the life of the device is likely to exceed the amount of time your current computer will be useful (I think I've seen estimates in the range of 3-4 years life--minimum--for newer, higher-capacity flash memory).
A more persuasive argument I've heard against using flash memory for swap is that access times for these devices can be much slower than SATA, and maybe even IDE, hard drives. That would certainly dictate against using flash memory for swap.
So, how about some input on this issue? Anyone using flash memory for swap? If so, what kind (e.g., usb stick or SD/CF)? Are you using a swap file or a swap partition? How's system performance? Likewise, has anyone had flash-memory-used-as-swap die on them? The consequences would undoubtedly be dire. Also, has anyone measured flash memory access times to confirm or refute claims about slow access times? Are some types of flash memory better/worse than others in terms of access times?
Lucid on an Acer Travelmate800.Can anyone tell me why I have 0k for swap space? I allocated swap which I can see in my Disk Utility's 'volumes' display.
I used Gparted to resize the swap area, and doing so changed the UUID so now the swap memory is not activated automatically and hibernation is also inactive. i got some info about this in a previous thread, which became inactive, and could not fix the problem.the output of sudo blkid is:Quote:
I did a standard install of Ubuntu 9.10, then upgraded to 10.04 LTS. Whenever I run htop I get:CPU [~3.8%] Mem [100/244MB] Swp [87/713MB]And free -mMem- total:244 used:214 free:29Swap- total:713 used:86 free:626It seems like I should be using allocating more memory to swap. I should be using more swap, or if this looks normal B. If so, how do I re allocate more memory to swap?I am new to linux and still trying to figure out a lot of things.
I've an 8GB swap (I know, overkill, but I don't have space issues, and I'd rather have too much instead of too less). The problem is that my physical memory fills up, and the system crashes, but swap usage is ALWAYS 0% Mem: 8060580k total, 5193436k used, 2867144k free, 1013788k buffers Swap: 8388604k total, 0k used, 8388604k free, 2262112k cached Setting aside the fact that I can't trace why memory usage goes up to 8GB with just firefox/terminals/pidgin, why isn't my swap EVER used?
Also, if I run Code: # top 2301 hugo 20 0 1887m 665m 38m S 19.9 8.5 267:38.63 firefox-bin 1811 root 20 0 166m 67m 10m S 10.8 0.9 128:04.59 X 1973 hugo 20 0 306m 78m 16m S 0.8 1.0 42:30.04 compiz 2024 hugo 20 0 487m 13m 8836 S 0.2 0.2 2:14.73 Terminal 1980 hugo 20 0 333m 7228 5492 S 0.1 0.1 0:54.49 lxpanel 7048 hugo 20 0 15016 1168 820 R 0.1 0.0 0:00.03 top (The rest are all "0 0 0 0 S 0.0 0.0")
If add up all of the RES columns, I get <1GB. If I add all the VIRT column, I get about 3GB. Where's the other 2GB being used? This goes up all the way to 8GB, without being able to add up where my memory's going.
There are plenty of tools for umounting/mounting/automounting usb flash/pen drives/dongles/hard drives. There's the Device Notifier on kde 4, for example.
But what about other devices like headphones, mice, keyboards, modems, etc? A tool for doing this would be very handy.
When we want to setup a linux system, there is a common a suggestion like set the swap space as twice as big than your physical memory, I want to know why do we need this and how is this suggestion come from?
I wonder why swap memory is not used! I also face auto-restart issue while running few tasks. Does it relate to the swap memory?
uanme -r -> 2.6.18-164.el5
I remember that my i have allocated about 5G for swap memory. However I put it into different partition and far away from root partition due to diskspace partition. Does it matter?
I do not know how to show the swap memory partition or partition map over here.
here is the mount output /dev/sda2 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw)
I have a system with 2G of memory and swap memory of 4G.
This is the output from :
PHP Code:
How could they do to the memory cache to be used as much? Because, occasionally, swap is used and note that the system could use the memory cache does not swap ...
In our cluster, both the server and worker had been gone to swap and the performance is extremely slow. Although currently the memory is free but I don't know why the in the swap area is still being there and ubuntu doesn't move them to the memory and empty the swap.
On the other hand, when I run
Code: sudo swapoff -a on the server it says: Code: mahmood@server:~$ sudo swapoff -a
i have a RAM of 1 Gb & swap of 1Gb with fedora11 installed, initially in RAM programme memory uses around 300 Mb & cache uses 600-700 Mb , but after some time it starts using swap memory though my programme memory is still around 300 mb, it keeps on increasing swap memory as a result my system keeps on slowing down & finally when swap memory is 100% system almost stops responding but programme memory is still around 300mb.
I run a memory-hungry process (mkcromfs) which consumes more memory than I have physical memory on my latop, so it is paging and swappin and thrashing all the time and loadavg is about 2 (compcache is already in use with usual swap partition as well), but slowly moving forward (Although I afraid it will finally try to allocate >2GB and crash draining 2 days of thrashing).
When I want to use the laptop for something else, I stop the process, start X server, firefox and other programs. The problem is that when I start Firefox the loadavg jumps to 10 and the system becomes almost unresponsive at all (long time to turn on/off caps lock, slow mouse cursor position updates, slow switching from X server to Linux console, slow login).
The stopped mkcromfs still holds a lot of memory (464.8 MiB and slowly falling) and moves it to swap only when more memory is needed for some other program, which results in a great slowdown.
How to tell the Linux to swap out this process entirely (e.g. I'm not intending to resume it in short term), possibly waking from swap other data? Also it will be useful to be able to specify the exact swap device to swap the given process out (for example, mkcromfs's memory is useless in ramzswap).
Update: Now I just write a 400-600M of data from /dev/erandom to tmpfs and it makes mkcromfs to shrink. Is there more proper way?
Nagios 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
I'm having problems using a swap file to increase swap space in Linux. I followed the instructions for creating a swap file, as shown here:
[URL]
It works, and I increased my swap space. But when I reboot, I'm back to the original amount of swap space I had before. The swap file I created is still there, but it's not being used as swap space. I tried remounting the swap file but it doesn't work.
Also, it seems there isn't an fstab entry created for the swap file. Strange, huh? I don't think it made a difference but I manually copied the UUID for the swap file and made an entry in fstab.
I may be wrong, but from what I can tell the UUID of the swap file keeps changing every time I reboot.
So basically every time I reboot I have to repeat the instructions shown above to get more swap space.
I want to move my swap file onto a new extended hard drive. Device Boot Start End Blocks Id System /dev/sda1 * 1 1243 9984366 83 Linux /dev/sda2 1244 1305 498015 5 Extended /dev/sda5 1244 1305 497983+ 82 Linux swap / Solaris
I want to put a 2Gb swap file on sda2. > dd if=/dev/sda2 of=/mnt/2Gb.swap bs=1M count=2048 0+1 records in 0+1 records out 1024 bytes (1.0 kB) copied, 0.000388458 s, 2.6 MB/s
Why is this only copying 1.0kB? Do I need to format the extended drive first? I have tried specifying the block size and count a number of different ways with the same results.
Currently running 10.04 and Cacti latest version and although my RAM is only just over 3/4 used my swap file is growing. If I leave the box running for about a week the swap fills and the system grinds to a halt.Is there some way of seeing what's in the swap so I can debug the problem and get my system more stable again?
a possibly preposterous question. I am aware that you can designate a swap file or swap partition on your hard drive that linux uses as "memory". Suggested sizes for the swap file that I've seen range up to about 1024MB. Is there a limit to the swap file size that you can set?Basically I am running a perl script that processes a massive B) file (DNA sequence data), etc, and requires around 48 GB of memory to run, maybe a bit less. So, would it be possible to set a swap file to a massive, ridiculous size (~60GB oratever) and successfully run such a script on a desktop?Yes, I am aware that it would massively ow down the process. The thing is, if the perl script normally completes in about half an hour, and I can get it working on a desktop, I don't mind if it takes days or weeks to complete. I really don't. That's because it takes days or weeks to get access to a computer with the required grunt to do it.So, is this a stupid idea? Is it even possible? If so, given a perl script that normally completes in a half hour on a 48G system, if you do this, would it take days? weeks? decades
I currently have Ubuntu Desktop 10.10 installed and have a great setup. However, I'm trying to install another OS on the hard drive and need to remove a partition. I've read online that I can remove the Swap partition and use a "Swap file". My question is this: Is it possible to replace the Swap partition with a "swap file" without having to re-install linux?
Dual-booting: Mac OS X 10.6.3 / Ubuntu Desktop 10.10 Macbook Pro 6,1 2.8 GHz Intel Core i7, 4 GB RAM
I have 2G of physical memory and 1G of memory swap. Very rarely the memory swap is used and when usage is around 1% while, then gets a lot of free physical memory...My question is:It is possible to "clean up" the memory swap. Or better still (I think). It is possible to spendphysical memory for data that is in memory swap?
Question: what command can I use swap item1 and item2 around and keep the attributes in place. A space seperates the first and second column. The file has many hundreds of lines in which these need to be swapped
I have a csv file of my students' names, but they're listed in the Asian order (last name, first name) and I need to list them in English order (first name, last name).
I know I can use something like awk, but that's usually substituting one thing for another. How can I get it to modify the names in a column in a csv file and swap the order? code...
I would want to switch "Tanaka Hiroto" to read "Hiroto Tanaka". There's about 500-600 names in the list, so doing this using CLI would save a lot of time.
I am sitting in front of an Ubuntu which was installed previously by someone else. How can I find out if a swap partition was defined?Is it always a swap partition or only a (ONE) swap file (like in Windows XP) ?If there is currently no swap partition: How can I create one and tell Ubuntu to use it?How can I conversely tell Ubuntu NOT to use a separate swap partition but to use
