TRIM – What is it?
When we talk about TRIM we aren’t referring to losing a few founds after Christmas, although I could certainly use that. TRIM refers to Solid State Drive and Flash technologies, which are now becoming more prevalent in Data Centres as well as our consumer world. If you look to buy a laptop these days there is a strong case for opting for a solid state drive to give you faster boot up times and performance. Similarly there are many options in the Enterprise market from true flash arrays like Violin to the PCI accelerator cards like Fusion IO. In order to understand TRIM you need to have an idea of how Flash storage works. SSD’s use NAND memory to store and transfer information in pages. A collection of pages makes up a blocks. You cannot delete a page, you can only delete a chunk of pages (block) So when you delete a file it actually just gets marked for deletion and at a later time when enough pages are available they are deleted. This practice slows down your super wizzy SSD drive over time. Think of it as a desk full of work, some pages you don’t need so you put on a recycling pile. But you don’t want to walk over to the recycling bin until you have a good pile. In the meantime you run out of paper, so you have to sort through and fish out some paper and rub out some doodles. This obviously will impact your productivity and this is why solid state drives slow down after prolonged use.
A TRIM command enables your Operating System to find pages marked for deletion and free them up for you. Think of it as a type of reclamation process. For this to work the SSD drive and the OS need to support TRIM. So for organisations looking to expand into the solid state market TRIM will be a consideration. Otherwise the initial performance seen may well plunge off a cliff over time and leave organisations feeling mis sold.
The good news is that Symantec’s Storage Foundation is here to the rescue. With Storage Foundation 6.0.1 they have introduced TRIM support with Linux (RH and SLES) with several SSD devices like the Fusion IO and IOdrive2. What this means is that by using Storage Foundation on your hosts you will be able to maintain your blistering performance in a predictable fashion. Expect more devices hitting the HCL as these become more popular in the commercial world. But for now it looks like TRIM is the standard that will enable the adoption of SSD technologies in a reliable fashion. Well done Symantec…