1 2 Previous Next 26 Replies Latest reply on Oct 10, 2015 3:00 PM by bigtom

    RAID 10 SSD performance?

    bigtom

      I have read a few places that SSDs in raid 10 are extremely slow for write speed. I am not sure why that would be. I was looking at using Softraid v5. Anyone have experience with this? I was thinking of upgrading from RAID 1 to 10, but if this is the case I will leave it alone.

        • 1. Re: RAID 10 SSD performance?
          bigtom

          I am not sure I need to worry too much even if it is a little slower. When I watch the activity monitor at 1sec interval even when the solution is being used heavily I am only seeing disk reads and writes around 3.5MB/s max. Usually it is 0 when record are only being browsed. Looks like the whole thing is being served from RAM Cache. I lowered Cache from 200MB to 64MB and it seems to not make a difference. The solution is 1.5GB with a lot of images but only low res thumbnails on the layouts. The rest of the text is cheap. 

           

          Quad core Mac Mini 2.6 with original dual SSD Server disks. I also want to get the database off the OS drive.

           

          The network send and receive can get to about 3.5MB/s when used heavily. I am starting to think I have an overkill disk system that ran at 400MB/s when I ran an intensive application on the server to test it.

           

          Running normally under heavy use It sits at 1.5Ghz, 55degC, and pulls less than 6W of power and never touches the hyper-thread cores. Running the resource intensive App on the machine to test it I settle around 2.8Ghz, 65degC, power between 10-20W. When I ran NickLightbody 's test suite the numbers would pin to the max on everything eventually. So I know the server has the guts to do a lot of work, but maybe just over provisioned.

           

          Do I really need RAID SSDs for the database? Any experience is appreciated.

          • 2. Re: RAID 10 SSD performance?
            taylorsharpe

            RAID10 would only be slow compared to RAID 0 which is no redundancy.  RAID 10 is usually the preferred database RAID.  The most common RAID is 5, but it has a high write penalty due to the parity stripe, and is less preferred by databases.  RAID 1 is simply two identical drives that the same read/writes go to each drive. 

             

            By the way, software RAID is fraught with issues and is not as efficient as hardware RAID.  For a production server, don't waste your time with software RAID.  What RAID hardware are you looking at?

            • 3. Re: RAID 10 SSD performance?
              bigtom

              Well I cannot seem to find hardware RAID 10 for SSDs. I have been running just fine for quite a while with software raid.

               

              I do not really have the space for a large RAID box. I appreciate the advice, but I am fairly set on software RAID with SSDs for now. Partly because of power consumption and space constraints. I understand the disadvantages. Currently running the OSX RAID utility.

               

              If you know of someone with a small hardware RAID 10 for SSD let me know. I was looking at the OWC mini enclosure. I prefer thunderbolt connection.

               

              I was asking about performance experience with SSD in Raid 10.

              • 4. Re: RAID 10 SSD performance?
                taylorsharpe

                RAID10 is not going to beneficial until you have 4 drives, as will most RAIDs.  If you just have two drives, then there is really no difference with going with RAID1.  With software RAID1, you probably are actually going slower than a single SSD by itself.  The only reason to use software RAID is for some redundancy, it is not helpful on performance and may actually decrease performance.  What type of computer hardware?  If you're just talking a Mac Mini... your best performance is a single SSD that is time machined to a second SSD.  The main reason I recommend this is that crashed drives are often recoverable as a single storage unit, but as one of multiple units in a RAID, they are virtually unrecoverable. 

                • 5. Re: RAID 10 SSD performance?
                  bigtom

                  I plan on purchasing 4 new drives. The point is redundancy. We have a good backup setup, but I was looking at making another small improvement. The software RAID would allow for a fast rebuild in case of a drive failure. Already running software RAID 1 and having no performance issues

                   

                  The only decrease I can see is some added time for the software to write to two extra drives. Yes, Mac Mini.

                   

                  This would allow me to setup the OS disk in RAID 0 for any benefit that might have for the FM Server running. Maybe none. Getting the databases off the OS boot disk is another goal.

                  • 6. Re: RAID 10 SSD performance?
                    bigtom

                    I did find a smaller 2.5" 4bay enclosure with a hardware controller for about $1500. That is not too bad I guess.

                    • 7. Re: RAID 10 SSD performance?
                      wimdecorte

                      Software-based RAIDs are NOT recommended.  If you want to use RAID, then definitely get a RAID controller card.

                      • 8. Re: RAID 10 SSD performance?
                        taylorsharpe

                        You said you wanted SSD drives.  What is the reason for wanting them?  I find often in hardware controlled RAIDs, SSDs often do not give better performance and they offer a lot smaller storage.  You said you needed small, which is why I assumed some 2 bay system.  But you say you are looking at 4 Bay systems.  Have you looked at things like the Promise Pegasus Thunderbolt 2 drives?  They have great performance using SATA drives.  I don't consider them big, but from your description, I thought that was too big.  But if you don't mind looking at RAIDs that size and assuming you want to take advantage of Thunderbolt speeds, a good comparison of available Thunderbolt RAIDs is as follows from over a year ago when Thunderbolt 1 was common.  Most of these have newer versions that are faster than below, but this is just a comparison I could find. 

                         

                        DASComparison.jpg

                        • 9. Re: RAID 10 SSD performance?
                          eoin

                          I personally wouldn't trust SSD in an enterprise database system ... unless they were rated enterprise class drives.

                          I'm also a little confused by the reasoning of raid 10 for redundancy and performance of the database file and Raid 0 for the OS and filemaker install.

                           

                          In my own case I chose a Promise pegasus2 6 bay enclosure with 4 drives as raid 10, a dedicated spare drive and the remaining drive as a passthrough volume. It has been quite stable with good performance for the past couple of months(FMS14)

                          • 10. Re: RAID 10 SSD performance?
                            wimdecorte

                            eoin wrote:

                             

                            I personally wouldn't trust SSD in an enterprise database system ... unless they were rated enterprise class drives.

                             

                             

                            That goes without saying, you wouldn't put consumer class SSDs in a server.

                             

                            eoin wrote:

                             

                            I'm also a little confused by the reasoning of raid 10 for redundancy and performance of the database file

                             

                            RAID is never for performance, it is ONLY for redundancy.   Obviously if you want that kind of redundancy you also want to make sure you don't too much of a performance hit.  Hence the need for hardware controlled RAID and not software RAIDs.

                             

                            When properly set up a RAID can be very performant, but that is *not* its main purpose.  The only purpose for a RAID is data protection.

                            • 11. Re: RAID 10 SSD performance?
                              eoin

                              I understand all that and I don't necessarily agree with you regarding performance to be had from certain raid setups, but I think you miss understood my question to the OP.

                              I'm confused by his decision for disk redundancy to host the DB file yet he chooses to use raid 0 with no redundancy for the OS and FMS install.

                              • 12. Re: RAID 10 SSD performance?
                                DavidZakary

                                If I've had a catastrophic failure that takes down the FMS machine, I'm probably going to do a completely fresh install of the OS and FMS rather than try to recover. Recovery can be very, very slow and I can't be guaranteed that I'm not recovering something that caused the failure. Reinstalling the OS is a couple hours, FMS is usually a pretty quick install.

                                 

                                Having the redundancy on just the database drive doesn't seem that peculiar to me at all.

                                • 13. Re: RAID 10 SSD performance?
                                  eoin

                                  Everyone has different opinions regarding best setups, I was curious as to the reason of the OP's choice of redundancy on one side(data) and none on the other(os/FMS)

                                  I would suggest given the Mac mini server being used as a FMS server it might perhaps be a better option for raid 1 setup with the two internalHDD of the mini giving  an element of redundancy in the event of a single internal disk failure.

                                  The overhead of writes to both disks for OS X and the FMS service would be pretty minimal.

                                   

                                  There is no right or wrong way, they will all work up until the point they fail. The key in my mind is giving yourself some options and breathing room to schedule a replacement or reinstall at a time that suits you and the users.

                                  • 14. Re: RAID 10 SSD performance?
                                    bigtom

                                    eoin wrote:

                                     

                                    I would suggest given the Mac mini server being used as a FMS server it might perhaps be a better option for raid 1 setup with the two internalHDD of the mini giving  an element of redundancy in the event of a single internal disk failure.

                                    The overhead of writes to both disks for OS X and the FMS service would be pretty minimal.

                                    This is exactly how it is running now already.  We are basically at the point where Apple Care will expire on the Mac Mini soon. Having an option where the databases are on an external drive and can easily be move to another machine if there is any issue with the current server. I guess this is good regardless of Apple Care anyway.

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