Synonym for: RAM - Acronym for: Random Access Memory, a type of computer data storage.

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172
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Any benefit or detriment from removing a pagefile on an 8GB RAM machine?

I'm running Windows 7 on a dual core, x64 AMD with 8GB RAM. Do I even need a pagefile? Will removing it help or hurt performance? Would it make a difference if this is a server or a desktop? Does ...
50
votes
10answers
6k views

Why drop caches in Linux?

In our servers we have a habit of dropping caches at midnight. sync; echo 3 > /proc/sys/vm/drop_caches When I run the code it seems to free up lots of RAM, but do I really need to do that. ...
50
votes
3answers
45k views

Meaning of the buffers/cache line in the output of free

Why does my server show total used free shared buffers cached Mem: 12286456 11715372 571084 0 81912 6545228 -/+ buffers/cache: 5088232 7198224 ...
40
votes
2answers
2k views

vSphere education - What are the downsides of configuring VMs with *too* much RAM?

VMware memory management seems to be a tricky balancing act. With cluster RAM, Resource Pools, VMware's management techniques (TPS, ballooning, host swapping), in-guest RAM utilization, swapping, ...
36
votes
3answers
20k views

In Linux, what is the difference between “buffers” and “cache” reported by the free command?

This is an old question that I've seen from time to time. My understanding of it is rather limited (having read about the differences a long time ago, but the factoid(s) involved never really stuck). ...
34
votes
5answers
12k views

How to understand the memory usage and load average in linux server

I am using a linux server which has 128GB of memory and 24 cores. I use top to see how much it is used. Its output is pasted at the end of the post. Here are two questions: (1) I see that each of the ...
33
votes
9answers
10k views

Linux: how to explicitly unswap everything possible?

I've launched something that took lots of memory and now everything lags a lot. I guess all applications' memory has gone to swap in order to free some space for the memory-intensive process, and now ...
32
votes
7answers
2k views

Database server: Small quick RAM or large slow RAM?

We are currently designing our new database servers, and have come up with a trade off I'm not entirely sure of how to answer. These are our options: 48GB 1333MHz, or 96GB 1066MHz. My thinking is ...
27
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9answers
5k views

To improve SQL performance, why not just put lots of RAM rather than having faster hard disks?

People keep telling me that in order to improve an SQL server's performance, buy the fastest hard disks possible with RAID 5, etc. So I was thinking, instead of spending all the money for ...
27
votes
9answers
27k views

How to reduce memory usage on a Unix webserver

I'm currently using a Joyent Accelerator to host my webapps, and it's working fine, however I need to reduce costs so I'm downgrading my current plan and that imposes some new memory limits (256M rss, ...
26
votes
3answers
16k views

Turn off the Linux OOM killer by default?

The OOM killer on Linux wreaks havoc with various applications every so often, and it appears that not much is really done on the kernel development side to improve this. Would it not be better, as a ...
23
votes
7answers
2k views

Is it necessary to burn-in RAM for server-class hardware?

Considering the fact that many server-class systems are equipped with ECC RAM, is it necessary or useful to burn-in the memory DIMMs prior to their deployment? I've encountered an environment where ...
22
votes
5answers
57k views

Top - what does Virtual memory size mean? …linux/ubuntu

I am running top to monitor my server performance and 2 of my java processes show virtual memory of up to 800MB-1GB. Is that a bad thing? What does virtual memory mean? And oh btw, I have swap of ...
20
votes
4answers
18k views

What is ECC ram and why is it better?

I've seen a dicussion about ECC ram use on servers. Why is it better?
20
votes
4answers
2k views

Can MySQL effectively take advantage of 64 GB RAM?

We have been running into a problem where querying a table that has approximately 50 million rows, and has an index size of 4 GB (table size of about 6 GB) results in the database server swapping ...
19
votes
7answers
13k views

Windows Server 2008 R2 Metafile RAM Usage

I have a server which runs Windows Server 2008 R2 x64 with 4GB of RAM which hosts around 2-3 million files, the majority of which are image files. Over a course of a week, I have noticed that ...
18
votes
8answers
51k views

Should you disable page file with SSD?

I've been reading this question, and it has a lot of great information. But assuming you have more than enough ram, I think page file should be disabled on SSD to extend the life time. I know you ...
16
votes
4answers
12k views

How can I determine the cause of an apparent memory leak in my Apache/PHP based web app?

About once a week, but sometimes even a couple of times a day after running fine for days, my EC2 instances become unresponsive. Munin's memory graphs tell a pretty straightforward story: memory ...
15
votes
6answers
30k views

How to find memory usage of individual Windows services?

Task Manager shows the overall memory usage of svchost.exe. Is there a way to view the memory usage of individual services? Note this is similar to ...
15
votes
5answers
2k views

Unusually high dentry cache usage

Problem A CentOS machine with kernel 2.6.32 and 128 GB physical RAM ran into trouble a few days ago. The responsible system administrator tells me that the PHP-FPM application was not responding to ...
14
votes
10answers
16k views

Memory usage per user in Linux?

Let's say i have 20 users logged on my linux box. How can I know how much memory each of them is using?
14
votes
4answers
52k views

DIMMs: Single vs. Double vs. Quad Rank

What difference does the 'Rank' of DIMMs make to server memory? For example, when looking at server configurations I see the following being offered for the same server: 2GB (1x2GB) Single Rank ...
14
votes
4answers
5k views

Mirrored Mode RAM: Is it worth it?

Not really familiar with Intel's "Mirrored Channel Mode" for a Blade Server setup (your typical moderately-heavy MySQL OLTP database running on the bare metal blade; no virtualization right now). ...
14
votes
1answer
10k views

How to interpret output from Linux 'top' command?

Following a discussion made HERE about how PHP-FPM consuming memory, I just found a problem in reading the memory in top command. Here is a screenshot of my top just after restarting PHP-FPM. ...
14
votes
2answers
20k views

page allocation failure - am I running out of memory?

Lately I've noticing entries like this one in the kern.log of one of my servers: Feb 16 00:24:05 aramis kernel: swapper: page allocation failure. order:0, mode:0x20 This is what I'd like to know: ...
13
votes
3answers
15k views

How to increase the amount of memory memcache uses?

I am currently on a Xeon 7550 server running Redhat x86_64 es5 with 32gb RAM. I have memcache installed and the only step remaining in the configuration is to set how much memory it uses. I had done ...
13
votes
13answers
9k views

Simple tool to graph memory usage?

Is there a script that will show memory usage as a graph, for example as a pie-chart, with each process being being a separate slice? I'm not looking for something like Munin to graph memory usage ...
13
votes
2answers
902 views

What RAM options do I need to know before buying Server RAM?

This is a proposed Canonical Question about Server Memory. I have to buy a Dell R420 server and there are various combinations (1600 and 1333 MHz RDIMMS and UDIMMS) and Performance Optimized vs. ...
13
votes
1answer
4k views

deleting linux cached ram [duplicate]

I have a webserver that has 8GB of ram and is running a pretty intensive php site (1 site) that does file manipulation, graphing, emailing, forums, you name it. The environment is far from static ...
13
votes
1answer
8k views

Memory Usage Numbers In top/htop

Can someone please explain this top output. Each PHP process is using 30% of the total memory or of the used memory? Furthermore how can it be that the combined used memory across all the PHP ...
12
votes
7answers
5k views

SQL Server - Force DB in memory?

We have a beefy Windows 2008 x64 server (4 x 4 core CPU, 32GB RAM) running SQL Server 2005 64-bit. We have a small (6GB) but very important database that is somewhat slow to access until the pages are ...
12
votes
2answers
6k views

Find out which database in SQL Server 2005 uses how much RAM

A friend of mine asked me today (trying to calm down an agitated customer of his) how you could find out in SQL Server 2005 which database uses how much memory (in the server's RAM that is) at any ...
12
votes
3answers
2k views

Balancing RAM when using multiple CPUs

We have HP DL360 G7 server with one cpu and 16G 12G ram. We plan to add another cpu. So, we need also ram for second cpu. Is there any negative performance impact if we add different size of ram to ...
12
votes
6answers
33k views

Weird memory usage in Windows Server 2008 R2

I hope someone can help. We've got a Windows Server 2008 R2 machine with 16GB of RAM that keeps getting all its available memory eaten by something. Nothing in Task Manager or Resource Monitor reveals ...
12
votes
7answers
2k views

How do I inventory the type and speed of a remote computer?

I'm on a Windows 2003/2008 corporate network with 100 users. I've been tasked with increasing the RAM on all end-user workstations. The problem is we have a mixture of different computers in our ...
12
votes
4answers
10k views

SQL Server 2005: There is insufficient system memory to run this query

One of our SQL Servers, which has been running stable for quite some time (years), has recently been throwing insufficient memory errors. From the Application Event Log, we see: Event ID: 701 ...
12
votes
3answers
2k views

Can you determine which Apache modules have been used and can be removed?

I, like many people, have a relatively out-of-the-box Apache installation with a lot of default "LoadModule" lines. Since the beginning, I've installed a lot of software, and to be honest, I don't ...
12
votes
6answers
11k views

After upgrading to 2008 R2 Enterprise and installing more RAM, Windows can only see 4.00 GB

(I have also posted this on technet but I'm running out of ideas) I've upgraded from Windows Server 2008 R2 Standard to Enterprise in order to make use of more RAM. The server previously had 32GB of ...
11
votes
2answers
4k views

How is memory usage reported in Linux?

Using ps, I can see the size, the vsize (same as top's VIRT?), and the rss (same as top's RES?). (One more I see in top is SHR.) Could someone summarize for me what these different fields mean?
11
votes
5answers
1k views

Linux with 256GB of mem / 48 Cores - Machine starts thrashing/choking with tons of memory left

Machine: Dell r815, CentOS 5.4, 256GB of RAM, 4 x 12 Cores. We have an application that has a 275GB file. It does an in place sort on 20GB of data at a time i.e. it swaps bits around and replaces ...
11
votes
3answers
6k views

Virtual Machine memory usage not appearing in TaskManager

There's something about Windows memory management and it's relationship to TaskManager that I don't understand and I'm hoping someone can enlighten me. If I'm running a virtual machine (doesn't ...
11
votes
2answers
12k views

Best Mysql cache settings for 8gb RAM dedicated mysql server using only Innodb (5gb database)

I'm a pretty big noob when it comes to setting up mysql for performance. And honestly I'm not worried about the fine tuning to squeeze every last bit of performance out of mysql, but I do know that ...
11
votes
5answers
30k views

How do I get SQL Server to release its memory?

I know SQL likes RAM, but releases it when Windows asks. I know this is how SQL is supposed to work. But I have a Windows Administrator who isn't convinced that SQL will actually return the RAM, and ...
11
votes
4answers
928 views

96 GB RAM on a Dell T7500 showing up as 78GB in Ubuntu Server 11.04

Running Ubuntu Server 11.04. I've got a new Dell Precision T7500 workstation loaded up with 12x8GB DIMMs and the BIOS shows 96GB but checking /proc/meminfo gives: cat /proc/meminfo | grep MemTotal ...
10
votes
7answers
5k views

Would you use ECC RAM in a workstation?

Is ECC RAM recommended for use in workstations, or is it something that only gets used in servers? If non-ECC RAM works in PCs, why would we need ECC RAM at all?
10
votes
4answers
5k views

Is it better to have more small ram chips or fewer large ones?

I am currently building a new server. I have options between say 32GB Memory for 2 CPUs, DDR3, 1066MHz (8x4GB Dual Ranked RDIMMs) and 36GB Memory for 2 CPUs, DDR3, 1066MHz (18x2GB Dual Ranked ...
10
votes
3answers
11k views

Why is Apache running so many processes? Excessive RAM here?

I notice Apache is running multiple processes on my LAMP server (ubuntu 10.10). I'm just running a Wordpress site with MySQL as a database. It seems like www-data is running apache2 more than it ...
10
votes
3answers
15k views

How to get - number of threads per process?

This is one Ubuntu 9.10 server. Also how to see memory usage per process? Thanks
10
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2answers
5k views

Linux: memory is free but swap is used. Why?

Here are Munin's diagrams. Memory usage: http://koryagin.com/w/q/memory-day.png Swap in/out: http://koryagin.com/w/q/swap-day.png Why does Linux decide to increase cache and use swap when the RAM ...
10
votes
1answer
495 views

Benefits to having a sole email VPS server

I have around 5 websites hosted in a VPS server, and for some reason I bought another VPS server recently just to host the emails for those 5 websites. I would like to know the pros and cons of having ...