Understanding and optimisng your SSD for maximum performance

 

Over the past few months I have optimised machines using newly purchased SSD and had to pass on this information to others. This is a consolidation of a few sources of information which hopefully you will find handy. It has been tried and tested but I do not accept any responsibility if you have luck or even bad luck with it. I ended up purchasing Samsung SSDs because of their capacity and the latest technology they were brining out, so you may need to interpret this for other SSD manufacturers, but most of the points below hold true no-matter the make of the SSD.

 

As with everything, please do the same as I did, research first test second, share third :)

 

   

Firstly it is worth while getting hold of the SAMSUNG magician software which tells you about a number of things you should be doing, if you don’t have the background already to configuring your SSD. It also has an additional advantage in that it can let you measure your disks performance without needing any other hardware

 

  

Starting from the PC architecture

 

1. SSDs can capitalise on the latest AHCI mode over the older IDE storage communication mode http://www.diffen.com/difference/AHCI_vs_IDE. This will boost your read and write performance of your SSD from 10% to 20% (or higher for some machines).
• CAUTION: If you have already installed Windows with a normal HDD, you need to edit your registry beforehand to ensure you machine will boot up if you change the AHCI setting in your BIOS - the instructions below are for Windows 8 and other operating systems will vary
• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\
• "Start" value should be set to "0" (Default is 3)
• "ErrorControl" value should be set to "0" (default is 3)
• "ImagePath" should contain "System32\drivers\storeahci.sys" and check that this file exists
• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\storahci\StartOverride
• "0" value should be set to data value of "3"
• Sometimes this entry is listed as "1" not "0" but this should still be the value to change 
• Please be aware that his is not a 100% guaranteed step, and you next alterative is to re-install Windows from scratch one you have AHCI turned on
2. Update your drivers which should boost you disk significantly and stop any false readings (on some machines the IO is reported as running @ 10% due to out of date drivers) and especially the "Intel Rapid Storage Technology" if you can get hold of it for your machines (Released 14/10/2012)
• Please ensure you go to your computer manufacturers support page and select the correct operating system before downloading the appropriate Serial ATA drivers.
3. Ensure you are running on SATA 3 and not SATA 2 as for example Dell 9010 machine only have 2 SATA 3 ports one of which is connected to the DVD and the second to the shipped HDD. This can give you a spead increase of up to 100% performance
4. Firmware updates are also important and for Samsung SSDs very easy to do.
• CAUTION: If a firmware update signifies it needs you to take a backup, then please do so.
5. Performance optimisation. A big misunderstanding exists behind disk defragmentation and SSDs. IN windows 8 the disk defragmenter is now called "Disk Optimiser". Both traditional HDDs and now SSDs need to be optimised which either moves files to eliminate fragmentation for HDDs and will clean up already used space on SSDs to ensure you can write to them faster. Please ensure you set a schedule in the Disk optimisers to optimise all your disks.
• Please note that SSDs must also write on clean space which means that they will have to clean up the space before writing to it, which costs two cycles as opposed to one. Hence disk optimisation simple truncates and wipes the space before hand.
6. Over Provisioning works in conjunction with disk optimisation but it also gives you one more advantage which you cannot gain by other means. It gives you
• Faster overall write IOPS and
• Better reliability with longer endurance of the SSD
1. CAUTION: Do this early on in the use of the disk or it can fail to happen afterwards.
2. All SSDs have a maximum number of writes per disk cell. So after that point the SSD cells will fail. To minimise this the SSD tries to spread all its writes evenly across the whole disk but as you can imagine this is a costly process, especially with small changes. Over provisioning allows you to keep some space free to both avoid the overhead of cleaning the disk before writing to it (and this also means less clean up operations) as well as it has a better way of provisioning new areas for use on the disk (minimising the amount of writes of files).
3. Finally over-provisioning can be used to extend the life of the SDD as it can both better optimise the clean up operations and be used to replace SSD space which is near its end of life (the dead pool).
4. Over provisioning 20% of the SDD has been measure to give a 250% improvement on write speeds of a full disk and overprovision of 40% has been measured up to 380% improvement.
5. Also Intel official white papers indicate that the over provisioning by 20% increases the endurance of a 160GB SSD by 400% so the writeable capacity of the SSD changes from 15TB to 61TB. @ 40% overprovisioning you get an additional 130% endurance and this increase is despite the fact we reduce the actual capacity available to the end-user.
6. But please note that the size of the write blocks is a big factor in determining the improvement and the measures above were based on 4k blocks.
7. And after all this is done its time to make sure your Windows settings are correct
• Turn off hibernation mode unless you really need it
• Fix you virtual memory settings
• Index Service and Searching is a debateable point and I usually turn this off when running VHDs on my SSDs
• Deactivate Prefecth/Superfetch
• Ensure Write cache buffer is enabled
• Active Write-cache buffer flashing
• Use maximum power setting for a system which runs VHDs
• System Restore is a space hog, use it wisely
8. New into the whole arena is RAPID Mode from Samsung. Available on 840 EVO and Pro disks it uses memory to significantly speed up read and write back with some amazing speed improvements of 100% on read and 50% on writes
• It can only be configured for a single disk in your system by using 1GB of your RAM, but it does introduce a significant risk if you do not have an uninterrupted power supply unit (UPS) as you run the risk of a power down leaving your system in an unpredictable state.
• I highly recommend leaving this setting turned off unless you can prove it has a benefit to your system as this feature only has specific measureable benefits but at the same time it can cause slow downs in other areas. See the "techereport" posted below were the Samsung 840 Evo disk actually drops in rating when Rapid Mode is turned on.

 

 

   

Sources of material

• http://www.diffen.com/difference/AHCI_vs_IDE
• http://www.ithinkdiff.com/how-to-enable-ahci-in-windows-8-after-installation/
• http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&cad=rja&sqi=2&ved=0CDcQFjAB&url=http%3A%2F%2Fwww.infortrend.com%2FImageLoader%2FLoadDoc%2F435&ei=O0xtUv_-PKaN0AXFyICwCQ&usg=AFQjCNGBpet0DIVCeHIWvPtQfMabrAQLFg
• http://www.storagesearch.com/ssdmyths-endurance.html
• http://www.storagereview.com/intel_ssd_520_enterprise_review
• http://www.youtube.com/watch?v=qE_5kRfzb6Y Samsung SSD 840 Evo Rapid Mode
• http://techreport.com/review/25282/a-closer-look-at-rapid-dram-caching-on-the-samsung-840-evo-ssd
•  

  

AX 2012 R3 Licencing for each Role, and the journey to creating it

For months now I keep thinking about creating a way to keep the AX 2012 security spreadsheets up to date, lost countless hours of sleep over it (well I lost a couple of hours over the last couple of days trying to solve this )

Why I hear you ask, well firstly because the licensing spreadsheets on the internet are copies from AX2012 RTM (pre-R2) and are out of date. Secondly because as soon as you try to create your own security the lists gets even more out of date. Many a client have asked me about it and it is handy to be able to see how each role is put together and what impacts the license.

So after days of hard SQL slog, 100 lines of extreme TSQL, some X++ code and avoiding the Eurovision contest (Hooray for bearded folk) you can now access the up to date, R3 compliant security/licensing spreadsheet.
 

Here is a link to an R3 up to date License/Security spreadsheet. Please take it as a rough report, showing you the Roles by number of license entry points in both a high level view and by duties/privileges http://1drv.ms/1mQ35MR. Each entry point is analysed against its license. “None” indicates that only a server license is required.

Also a full analysis spreadsheet can be downloaded with full entry point disclosure e.g. Menu items http://1drv.ms/1mQ2ZF4

Shared as an Excel Online spreadsheet in Onedrive.

The methods I used to achieve this results is worth noting, just in case you want to do this yourselves. To achieve this report I needed four things

• The Entry points for each privilege and the appropriate License
• The complete hierarchy of  all AX security from Roles, Sub-Roles, Duties and Privileges
• The labels for all the AX objects
• A way to combine all the above in a meaningful manner

So the first thing to note is that AX 2012 has a class which calculates the licenses per user, but only needs to do this by entry point and role. The class even has a helpful way to set up the batch job. I am of course referring to

SysUserLicenseMiner::createBatchJob();

 If you look through this class you will find two temporary tables which actually get truncated when the batch job runs. The table I need is the one concerned with licenses

SysUserLicenseMetadataTmp

I simply changed this from a TempDB table to a Regular table, as it is very useful to retain and its is not that big. 

So Entry points at hand I looked at the System Tables and found the Security Tables I needed to work out the hierarchy, better still there are a number of views based on these tables which helped me understand their purpose. Using SQL Management Studio i found out the following tables in the AX_Model database (where AX is replaced by your AX Database name)

• ModelSecurityRole table holds all the key fields for all security artifacts as well as label reference Ids. Please note though this may have duplicate entries to accommodate layers. Hence many views group the records by RoleHandle (the security artifact unique ID) and use Max(RoleLayer) to find the highest layer for the artifact
• ModelSecuritySubRole table contains all the relationships between artifacts e.g. how Duties related to roles
• ModelSecurityPermission is the link between privileges and entry points, but you will need ModelSecurityCommon to go from a Named Entry Point to an ObjectHandle. Please note, entry points may require both an object and a child name e.g. server class and method name.
• ElementTypes is a handy table to lookup types of objects and join this for more meaningful description. You will do well to look up other values in the System enums
• ModelElementLabel is the language specific labels you will need to make things more meaningful to users

So now I have all the data, I had to work out the best way to decipher the info and construct a report. Given my experience in SQL I knew this would be a lot faster and more portable if I used TSQL to do this. TSQL is slower to produce than writing X++ code but it avoids any major system changes and is 100s of times faster from experience, well at least good SQL is faster :)

• I used CTE (Common table expressions) to work through the recursive parts, but I ultimately used it to break the whole problem into unique Roles, unique & cascading sub-roles, unique & cascading duties, unique & cascading privileges and entry points
• I decided that I would adjust the cascading structure and make it more consistent to enhance  readability of complex scenarios and simplify the TSQL, so it should have exactly five levels as follows

• Role 1
• Role 1 acting as a sub-role
• Duties
• Privileges
• Entry Points
• Add Duty to group Role based Privileges 
• Privileges from Role
• Entry Points
• Sub-Role1
• Duties etc
• Flattened Sub-Role 1.1 (from Sub-Role 1)
• Duties Etc
• Roles 2 etc

•  My final joins became easy due to the re-structure
• Select Flattened Roles, Sub-Roles, Duties, Privileges and Entry Point

• Finally I used a Pivot to change the license types into columns to simplify the report for users

And  the report was completed in such a way as to be ultra portable and flattened into an Excel tables. I was so glad I did that when I spotted the server only had Excel 2010 without Power Pivot, especially as I can hear you all complain about the flattened structure and duplication of data I had to use.

I am sure my next version will be a cascading table, separate label table and an entry point fact table for the licenses, but for now this will more than suffice.

I can run the routine any time I like, especially after any security changes and it only takes 30 seconds to populate the report. The entry point batch process runs once a night but I can also run this manually, and this takes 10 minutes to run.

I am not enclosing the TSQL as this is way to long for me to add a full explanation, and I want to change it to accommodate parameters and selection of db names, so for now the extracts will have to suffice, unless you try to contact me and allow me some time to explain it to you personally.

Enjoy the licensing spreadsheet, I know I had fun creating it.