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-   -   High-performance laptops, especially in the hard drive (

onebuck 04-09-2012 10:28 AM

Member response

I would use a ramdisk at the sacrifice of some memory. Or you could get dedicated ramdisk to place in the system.

SSD System Cache Set Up Guide may help if you happen to be using Intel SSD. I am sure you can find information for other manufactures.

Another good article: SSD Caching versus Tiering understand caching techniques.


TobiSGD 04-09-2012 10:41 AM


Originally Posted by Ulysses_ (Post 4648304)
Maybe a small SSD is faster than a large SSD for the same money?

Normally it is the other way around. Larger SSDs are usually faster, because they have more Flash chips that can be interleaved for better performance.


I would use a ramdisk at the sacrifice of some memory.
That is what I do. Works fine.

@Ulysses: You wanted an advice about the system with the most performance storage subsystem, regardless of cost. Here is mine: Use RAM for the tasks that need the most performance and fit into RAM (compiling large pieces of software in RAM is not a problem on a machine with 16GB). Use the SSD for storing your OS and tasks that need performance, but fit not into RAM (like your VMs). Use a second, mechanical, disk for storage and tasks that do not need a lot of performance.
This way you will get the best performance.

Ulysses_ 04-09-2012 11:17 AM

This is useful information, and surprising regarding small v. large SSD performance. One thing to note though: I have an old laptop with plenty of ram, about 3 times the ram given to each VM, and when one VM is running, the host operating system uses about half the remaining ram for disk cacheing, and if this VM is booted with more ram forcing the host cache to get smaller, guess what happens to VM disk performance. VM disk performance improves with a smaller host cache! So ramdisks are probably a bad idea for the host, any spare ram is handled better if given to the VM and the VM takes care of disk cacheing better.

SSD as a cache has a second advantage over ramdisks: it is persistent so when you power up the laptop it should boot as fast as if you're booting from an SSD. Is it?

H_TeXMeX_H 04-09-2012 11:30 AM

Another thing to look into is zcache. I've used it for a while and it boosts performance significantly, especially during heavy disk I/O. It lets you use RAM more efficiently, and reduces disk I/O. It plus other patches have solved issues with I/O hogging for me.

Ulysses_ 04-09-2012 03:49 PM


Originally Posted by H_TeXMeX_H (Post 4648408)
It plus other patches have solved issues with I/O hogging for me.

Any links for those patches?

H_TeXMeX_H 04-10-2012 05:00 AM


Originally Posted by Ulysses_ (Post 4648627)
Any links for those patches?

The patches were merged with the kernel above 3.2, so just use a kernel above that.

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