1 2 Previous Next 27 Replies Latest reply: Jun 8, 2014 9:47 PM by BVV Go to original post RSS
      • 15. Re: Storage initiators issue - assistance needed
        BVV

        NAS (1)    Normal    3766.5    Generic_iSCSI_Volume_Group    Thecus    iSCSI    fs_Repository_01    server02 and 1 others    Oracle Generic SCSI Plugin    

           

        Name:    14e415300000000000000000001000000692f000000001000

        Status:    Online

        Shareable:    Yes

        Thin Provision:    Yes

           

           

        Access Groups:   

        Repositories:    Repository_01

        Reserved:    No

        Reserved by Server(s):    N/A

           

        ID:    0004fb0000180000361d1789f15df02d

        Page83 ID:    14e415300000000000000000001000000692f000000001000

        Path:    /dev/mapper/14e415300000000000000000001000000692f000000001000

        Extra Information:   

         

         

            NAS (2)    Normal    3766.5    Generic_iSCSI_Volume_Group    Thecus    iSCSI         server02 and 2 others    Oracle Generic SCSI Plugin    

           

        Name:    14e4153000000000000000000010000005a2f000000001000

        Status:    Online

        Shareable:    Yes

        Thin Provision:    Yes

           

           

        Access Groups:   

        Repositories:   

        Reserved:    No

        Reserved by Server(s):    N/A

           

        ID:    0004fb000018000029f132ab50682ec8

        Page83 ID:    14e4153000000000000000000010000005a2f000000001000

        Path:    /dev/mapper/14e4153000000000000000000010000005a2f000000001000

        Extra Information:

        • 16. Re: Storage initiators issue - assistance needed
          budachst

          Are NAS(1) and NAS(2) actually the same target frpm the Thecus NAS? If they are both actually the same target, then I'm wondering, why they do have different Page83 IDs…

          • 17. Re: Storage initiators issue - assistance needed
            BVV

            Yes, they are exactly the same share... I have no idea whatis going on here and how to move on with this...

            • 18. Re: Storage initiators issue - assistance needed
              budachst

              Hmm, I had a Thecus NAS once, but I don't remember it showing this strange behaviour. The differen Page83 IDs are the reason, why you are seeing two incarnations of the same target. The only thing I can suggest is to check the iscsi target config on your Thecus. It really shouldn't issue different IDs for the same target on different initiators.

               

              I know, though, that the Thecus GUIs don't allow for much control over the actual iSCSI target setting. You might be better off, serving your storage via NFS.

              • 19. Re: Storage initiators issue - assistance needed
                BVV

                I solved the problem the most brutal way possible. I backed up the machines to another drive, re-created RAID on my Thecus, created NFS shares this time as you suggested and even reinstalled whole VM Manager and servers and now everything works fine as for repositories.

                 

                One thing I find strange: I run two Virtual environments based on OVM 3.2.2 (fibre channel, iscsi, etc) and each time I create/restore template it takes maybe a minute or so. When I installed the abovementioned environment (I used OVM 3.2.8) restoring the template takes a loooooong time (aproximately 1GB/min). I do not know those technologies much but is it possible the performance went down because I switched from iscsi to nfs? Or is it OVM 3.2.8??

                 

                Best regards,

                BVV

                • 20. Re: Storage initiators issue - assistance needed
                  budachst

                  Yes, that's one of the drawbacks of using NFS, since NFS doesn't offer reflinks, as OCFS2 does, which is used by OVM on LUN-based storage like FC or iSCSI. OCFS2 also supports sparse volumes, such as that creating a 1TB vdisk doesn not need significantly longer than creating a 10GB disk, which is of course not the case on NFS. This is the reason, why I solely rely on iSCSI or FC for all of my OVM storage.

                   

                  On the other hand NFS is easier to setup and maintain…

                  • 21. Re: Storage initiators issue - assistance needed
                    user12273962

                    With the right NFS environment.... you can get almost identical #s with NFS as with FC or iSCSI. Especially using 10GB ethernet. Many people try to compare an 8gb or 16gb FC link to a 1gb nic. There is no comparison. If you're going to strickly use 1gb nics.... then its probably not a good idea to NFS for a repo. Cluster pools filesystems are fine.

                    • 22. Re: Storage initiators issue - assistance needed
                      budachst

                      I totally agree, performance wise. However, the missing features like sparse files and reflinks still are very handy.

                      • 23. Re: Storage initiators issue - assistance needed
                        BVV

                        So I need to switch back to iSCSI and hopefully I will encounter no issues I have had anymore.

                         

                        A quick one at the end:

                         

                        NFS aside, I have two repositories created on physical disks attached to the servers in abovementioned pool. The performance of the machines located on those disks is plain horror. I have never seen such slow machines which suprised me because those disks were attached to the same server when they were running OVM 2.2. Do you know where to look for the issue?

                        • 24. Re: Storage initiators issue - assistance needed
                          budachst

                          You have created some local storage repository on your servers and the performance on those sucks? Are those single-pool repos? To get a figure of what's happening, you should run iostat and see what the numbers are.

                          • 25. Re: Storage initiators issue - assistance needed
                            BVV

                            Yes, those are the repositories in the same pool. I created them because I had some spare disks in order to have some space in case I had to turn main repository (Thecus) off.

                             

                            iostats:

                             

                            First server:

                            Device:     rrqm/s   wrqm/s   r/s   w/s   rsec/s   wsec/s avgrq-sz avgqu-sz   await  svctm  %util
                            dm-0          0.00   596.37 21.29  7.6487.58  4832.29   170.04 8.33  287.78   2.04   5.89

                             

                             

                            Second server:

                            Device:     rrqm/s   wrqm/s   r/s   w/s   rsec/s   wsec/s avgrq-sz avgqu-sz   await  svctm  %util
                            dm-0          0.00 0.00  0.02  0.00 0.19 0.01 7.97 0.00   17.78   2.36   0.01

                             

                             

                             

                            So you have a clear picture: I tried to install Oracle Linux 5u10 yesterday and installation took almost 2 hours.

                            I tried to install Win Seerver 2008 and took almost as long as the Linux.

                            • 26. Re: Storage initiators issue - assistance needed
                              budachst

                              if you've made the repos from a single disk, then you will be severely limited in the number of IOPs, that this repo can handle. So, should you be running more VMs from it, then the performance will  likely suffer from that. Also, you should take a couple of samples using iostat… like this:

                               

                              iostat -xm 5  -c 5 dm-0

                               

                              This will take the average of 5s 5 times, so you can see where you're heading at.

                              • 27. Re: Storage initiators issue - assistance needed
                                BVV

                                Thank you guys for your help. I rebuilt the whole environment using iSCSI from external storage and now works fine :-)

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