Best Jvm Arguments For Mac 4 Gb Ram

Posted By admin On 15.02.22
Active6 years, 1 month ago

I am a newbie to servers and management and I am trying to understand the relationship between RAM and JVM. Say, I have a server having 16 GB physical memory (RAM). I have an application running in Websphere. There are 4 application servers in Websphere each running the same application. We have allocated 2 GB JVM in each of the 4 application servers. I am assuming, 8 GB of RAM is consumed by the application as JVM and remaining 8 GB is free. In this case, is the free 8 GB utilized for someother purpose? Now is it possible to add 5 new application servers each allocated 2 B JVM. In other words, what is the relation between RAM and JVM. Can the sum of JVM added exceed the RAM?

Two great things about upgrading your PC memory are 1) that it’s cheap – especially when you consider how dramatically a new RAM stick or two improves your computer’s performance – and 2) it’s easy to add to your current computer setup. Then add the amount of RAM you would like to the JVM Arguments text box. For example if I wanted to run it with 1GB I would simply type -Xmx1G and the 1G will indicate 1GB of RAM. Xmx indicates the maximum RAM to allocate.

P.S. I am a newbie, please excuse if my question doesn't make sense. I am trying to understand how the application utilizes server memory (allocated as JVM).

Kannan LgKannan Lg

2 Answers

In this case, is the free 8 GB utilized for someother purpose?

If at all possible, yes. Making RAM free is a pure cost for the OS -- it just has to make it used again in order to use it. Unless the OS has no choice, it will use the RAM for some other purpose. The most common use is data that has been recently read from, or written to, disk. By keeping it in memory, the OS avoids the hassle of having to make it free just to make it used again, and if the very same data is needed, it saves a disk read operation.

Now is it possible to add 5 new application servers each allocated 2 B JVM. In other words, what is the relation between RAM and JVM. Can the sum of JVM added exceed the RAM?

Sure. The JVM's are allocating virtual memory, not physical memory. The OS will assign physical memory to virtual memory as necessary and efficient. Modern operating systems can allow virtual memory consumption to significantly exceed physical memory. This may or may not lead to poor performance, depending on the working set size -- roughly how much of the virtual memory is actually accessed.

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David SchwartzDavid Schwartz
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We have allocated 2 GB JVM in each of the 4 application servers.

I'd assume that you set the max heap size as 2 GB in each of the application servers? In that case, the size of your java process will actually be larger, as the java process will consists of the heap size 2 GB + the amount of native memory that the java process need. The amount of RAM the native memory the java process needs depends on the application, and unfortunately, cannot really be tuned. Therefore, when and if your application reaches the max heap of 2 GB, the size of your java process could be anywhere from 2.5 to 3.5 GB, possibly higher.

Therefore, keep this in mind if you have to allocate additional JVMs on your AIX box, so that it doesn't ran out of physical memory and starts paging.

Victor ChanVictor Chan

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Best Jvm Arguments For Mac 4 Gb Ram

Learn how to identify your iMac, then find it below.

Mac 4 Gb Ram So-dimms Of 1333 Mhz Ddr3 Sdram

iMac ModelMax. DRAMUser-
Installable
Slot
AASP-
Installable
Slot
Video/
VRAM
Notes
iMac (Retina 5K, 27-inch, 2019)64GB2666MHz DDR44GB or 8GB GDDR5 SDRAM5
iMac (Retina 4K, 21.5-inch, 2019)32GBNone2666MHz DDR4 (for i5 processor)
2400MHz DDR4 (for i3 processor)
2GB, 4GB, or 8GB GDDR5 SDRAM3
iMac (Retina 5K, 27-inch, 2017)64GB2400MHz DDR44GB or 8GB GDDR5 SDRAM5
iMac (Retina 4K, 21.5-inch, 2017)32GBNone2400MHz DDR42GB or 4GB GDDR5 SDRAM3
iMac (21.5-inch, 2017)16GBNone2133MHz DDR4Intel Iris Plus Graphics 6403

iMac (Retina 5K, 27-inch, Late 2015)

32GB1867MHz DDR32GB or 4GB GDDR5 SDRAM4
iMac (Retina 4K, 21.5-inch, Late 2015)16GBNoneIntel Iris Pro Graphics 62006
iMac (21.5-inch, Late 2015)16GBNoneIntel Iris Pro Graphics 60006
iMac (Retina 5k, 27-inch, Mid 2015)32GB1600MHz DDR32GB GDDR5 SDRAM4

iMac (Retina 5K, 27-inch, Late 2014)

32GB1600MHz DDR32GB or 4GB GDDR5 SDRAM4
iMac (21.5-inch, Mid 2014)16GBNoneIntel HD Graphics 5000
iMac (27-inch, Late 2013)32GBPC3-12800
(1600) DDR3
204-pin
SO-DIMM

1GB GDDR5 SDRAM,
2GB GDDR5 SDRAM and 4GB GDDR5 SDRAM

iMac (21.5-inch, Late 2013)16GBNonePC3-12800
(1600) DDR3
204-pin
SO-DIMM
Intel HD Graphics 4000
iMac (27-inch, Late 2012)32GBPC3-12800
(1600) DDR3
204-pin
SO-DIMM

512MB GDDR5 SDRAM,
1GB GDDR5 SDRAM and 2GB GDDR5 SDRAM

iMac (21.5-inch, Late 2012)16GBNonePC3-12800
(1600) DDR3
204-pin
SO-DIMM
512MB GDDR5 SDRAM
iMac (27-inch, Mid 2011)16GBPC3-10600
(1333) DDR3
204-pin
SO-DIMM

512MB GDDR5 SDRAM and
1GB GDDR5 SDRAM and 2GB GDDR5 SDRAM

iMac (21.5-inch, Mid 2011)16GBPC3-10600
(1333) DDR3
204-pin
SO-DIMM
512MB GDDR5 SDRAM
iMac (27-inch, Mid 2010)16GBPC3-10600
(1333) DDR3
204-pin
SO-DIMM

512MB GDDR3 SDRAM and
1GB GDDR5 SDRAM

iMac (21.5-inch, Mid 2010)16GBPC3-10600
(1333) DDR3
204-pin
SO-DIMM
256 MB up to 512MB GDDR3 SDRAM
iMac (Late 2009)16GBPC3-8500
(1066) DDR3
204-pin
SO-DIMM
256 up to 512MB GDDR3 SDRAM
iMac (Mid 2009)4GBPC3-8500
(1066) DDR3
204-pin
SO-DIMM
256 up to 512MB GDDR3 SDRAM
iMac (Early 2009)8GBPC3-8500
(1066) DDR3
204-pin
SO-DIMM
256 up to 512MB GDDR3 SDRAM
iMac (Early 2008)4GBPC2-6400
(800) DDR2
200-pin
SO-DIMM
128 or 256MB GDDR3 SDRAM
iMac (Mid 2007)4GBPC2-5300
(667) DDR2
200-pin
SO-DIMM
128 or 256MB GDDR3 SDRAM
iMac (Late 2006)4GBPC2-5300
(667) DDR2
200-pin
SO-DIMM
128MB GDDR3 SDRAM1
iMac (Mid 2006) and iMac (17-inch Late 2006 CD)2GBPC2-5300
(667) DDR2
200-pin
SO-DIMM
64MB GDDR3 SDRAM
iMac (Early 2006)2GBPC2-5300
(667) DDR2
200-pin
SO-DIMM
128MB GDDR3 SDRAM
  1. Although iMac (Late 2006) accepts up to a 2GB SO-DIMM in each of its two memory slots, the computer only supports 3GB total memory.
  2. iMac (Late 2009), iMac (Mid 2010), and iMac (Mid 2011) have four SDRAM slots, each of which can accept a 2GB or 4GB SO-DIMM.
  3. These iMac models have no user-installable SDRAM slots. An Apple Authorized Service Provider (AASP) can install SDRAM in these computers.
  4. 27-inch iMac models introduced in 2012 through 2015 have four SDRAM slots, each of which can accept a 4GB or 8GB SO-DIMM.
  5. 27-inch iMac models introduced in 2017 and 2019 have four SDRAM slots, each of which can accept a 4GB, 8GB, or 16GB SO-DIMM.
  6. Learn more about integrated video on Intel-based Macs.

Learn more

Learn about integrated video on Intel-based Macs

Get more information about memory and specific iMac models: