SUBSIM Radio Room Forums



SUBSIM: The Web's #1 resource for all submarine & naval simulations since 1997

Go Back   SUBSIM Radio Room Forums > General > General Topics > PC Hardware/Software forum
Forget password? Reset here

Reply
 
Thread Tools Display Modes
Old 08-22-17, 04:27 PM   #1
Skybird
Soaring
 
Skybird's Avatar
 
Join Date: Sep 2001
Location: the mental asylum named Germany
Posts: 40,340
Downloads: 9
Uploads: 0


Default SSDs

It is said that SSDs do not need to be defragmentised, that it even can be harmful to the durability of an SSD to do so. However, Noel Carboni'S severla comments here

https://www.askwoody.com/forums/topi...youre-getting/

kept me wondering whether that really is true. He insists that SSDs do fragmentise, but that it plays a less prominent role due to their much faster access time, however, people in the knowledge he claim to know who do it once per year.

Then there is the alterntive to use TRIM command instead.

Anyone in the knowledge about SSD and the need to fragmentise or not to do so?

Lets ignore the faster access time, everybody knows that. What about other factors to decide between SSD and HD? And if it is reliability before speed what you want, is an NAS-certified HD like WD's Red Pro series the option of choice?

Finally, how long is the durability of SSDs today, lets say very good ones like they say Samsung builds them? Are they to be replaced every two years? Do they last shorter, muchz longer today? Noel Carboni says he uses some for over five years now - without a single dropout so far.

Also, consider this:

https://www.hanselman.com/blog/TheRe...ntYourSSD.aspx

Quote:
Actually Scott and Vadim are both wrong. Storage Optimizer will defrag an SSD once a month if volume snapshots are enabled. This is by design and necessary due to slow volsnap copy on write performance on fragmented SSD volumes. It’s also somewhat of a misconception that fragmentation is not a problem on SSDs. If an SSD gets too fragmented you can hit maximum file fragmentation (when the metadata can’t represent any more file fragments) which will result in errors when you try to write/extend a file. Furthermore, more file fragments means more metadata to process while reading/writing a file, which can lead to slower performance.

As far as Retrim is concerned, this command should run on the schedule specified in the dfrgui UI. Retrim is necessary because of the way TRIM is processed in the file systems. Due to the varying performance of hardware responding to TRIM, TRIM is processed asynchronously by the file system. When a file is deleted or space is otherwise freed, the file system queues the trim request to be processed. To limit the peek resource usage this queue may only grow to a maximum number of trim requests. If the queue is of max size, incoming TRIM requests may be dropped. This is okay because we will periodically come through and do a Retrim with Storage Optimizer. The Retrim is done at a granularity that should avoid hitting the maximum TRIM request queue size where TRIMs are dropped.
__________________
If you feel nuts, consult an expert.
Skybird is offline   Reply With Quote
Old 08-23-17, 12:37 PM   #2
Rockin Robbins
Navy Seal
 
Join Date: Mar 2007
Location: DeLand, FL
Posts: 8,899
Downloads: 135
Uploads: 52


Default

The chance that there would be so many fragments that the system couldn't track them is almost zero for close to 100% of users. Your average person would have to work on hundreds of files, saving multiple versions per day for several years before that would ever be a factor.

On the SSD you are seeking a balance between the consequences of fragmentation (close to zero over a 4 year period for most of us) and the limited number of read/write cycles before a memory address breaks down and becomes unusable on an SSD. An SSD should only be used for system files which are infrequently changed, not for data. In that case defragging should never be necessary and your SSD will last its longest.
Rockin Robbins is offline   Reply With Quote
Old 08-23-17, 05:34 PM   #3
Skybird
Soaring
 
Skybird's Avatar
 
Join Date: Sep 2001
Location: the mental asylum named Germany
Posts: 40,340
Downloads: 9
Uploads: 0


Default

I weould not have used SSDs for database archives, as an example, but you reocmmend to also not use it for for exmaple sims/games, or any other software that gets used as a tool, for work, etc...? Only the OS installation?

Samsung has 2 TB SSDs now. What are they good for then? They give ten years warranty for their top models (850 Pro), but they cost almost one thousand Euros.

And were huge data volumes not one of the reasons why everybody wanted SSDs when they came out - so that working in a database environment is faster?
__________________
If you feel nuts, consult an expert.
Skybird is offline   Reply With Quote
Old 08-23-17, 06:21 PM   #4
thereddaikon
Watch
 
Join Date: Jul 2017
Posts: 22
Downloads: 9
Uploads: 0
Default

The short answer is no don't defrag an SSD.


The long answer is more complicated but I won't drag on too much. There's plenty of great write-up on the web that explain SSD operation better than I can. I recommend checking out Anandtech they did some great articles on the topic when they first hit the market 10 years ago.

So SSDs can and do fragment, all storage will with use. However a conventional defragmentation process is bad for the life of the drive because the memory blocks in flash have a finite number of read/write passes that can be made. This is also technically true of disk drives but the number is less strict and factors in other variables such the workloads the drive sees and environmental concerns like heat. A cool and easy used hard drive is a happy drive. I have hard drives pushing 30 that still work. With flash memory it comes down to the actual number of read/writes. Think of it like the difference between a gas powered car and an electric one. A gas car can run over a million miles if it's well cared for and never driven hard. But an electric car with batteries that have had the charge cycles for a million miles will have flat batteries. Li-ion batteries lose capacity as a function of charge cycles just like an SSD looses capacity as a function of write cycles.

This is where TRIM comes in. Think of it like the SSDs flavor of defrag. It's not that simple but for our purposes I'm making it that simple. Windows 7, still the most popular version does not have inbuilt support for TRIM. It predates widespread SSD adoption. Windows 8 and up do. So if you are going to use an SSD I recommend using Windows 10. Not only does it support TRIM but it also supports DX12 and this is a forum about computer games so I'll assume that's an important quality. As for when and how to run. Don't. It's automatic and takes care of itself. All you have to do is not run that defrag and screw it up. I was an early adopter of SSDs and things have gotten a lot better as time has gone on. The earliest drives were unreliable and with Windows 7 couldn't TRIM. I was lucky to get a year out of the things. Now they are as near as reliable to disk drives as make no difference for a PC. We've even started to use them in servers lately. The performance gains for a high availability SQL database are not to be dismissed.
thereddaikon is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 02:09 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright © 1995- 2024 Subsim®
"Subsim" is a registered trademark, all rights reserved.