Looking to replace existing 2 node cluster SQL server, interested in the PowerVault MD3220 DC Storage - For Small & Medium Business - Forum - For Small & Medium Business - Dell Community

Looking to replace existing 2 node cluster SQL server, interested in the PowerVault MD3220 DC Storage

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Looking to replace existing 2 node cluster SQL server, interested in the PowerVault MD3220 DC Storage

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Hi,

We currently have a 2 node clustered MS SQL that runs on 2x 2950 Dell PowerEdge Server that are then connected to an EMC (AX150iSC) via iSCSI using separated/isolated 1Gbps Ethernet switches.  We are looking at replacing/upgrading the EMC SAN box and are interested in the Dell's Direct Connected Share Storage solution based on the PowerVault MD32xx.  My question is how would that work regarding our failed over setup.  And what do I need on the server side?  Do I just need external SATA ports and do we need to also upgrade our current PE2950 server.  My understanding is this would greatly enhance our drive access performance without much loss in redundancy, is that corrected?

Any other information would be great since we are very new to the Shared Direct Connected Storage.  Any other solution that would be equilvaent in terms of performance/price would be good to know too.

Thanks

 

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  • Here is some info that may help:

    1. You will need to get at least 2 Dell SAS6E (these are dual-port) adapters (one for each server) with the MD3200 for connectivity with 2 cables per adapter (connect to both controllers on the MD3200). If you want adapter redundancy you can use 2 of these SAS6E adapters and either use all 4 ports (2 to each MD3200 controller) or just 1 port per controller. You'll want to get the appropriate number of cables for this (4 or 8 total depending on your needs).

    2. Migrating this will require full downtime and may require a full backup and restore of your SQL DB. Installing the MD3200-series failover software will most likely break Powerpath (I assume this is installed on both your servers for the connectivity to the AX150i). For this reason you would need to uninstall Powerpath prior to installing MDSM (Modular Disk Storage Manager (the MD's management and host (failover) software)). When you uninstall Powerpath you could lose disk access to your AX150i's storage. It's possible that if you are only using a single connection from each server to the AX150i that you could be running without Powerpath (or that it would work fine after uninstalling).

    3. The AX150i only supported 7200rpm SATA drives. The MD3200 only supports SAS drives. These can be 7200rpm (called Near-line SAS), 10k or 15k rpm drives. Even if performance never was an issue, don't assume that you can just go with fewer larger drives (of the same speed) and expect the same performance. A 7200rpm drive can yield about 80 iops in maximum performance potential. If you had 11 drives in a raid 5 or so (1 hotspare), you had a max performance potential of ~623 iops at a 90/10 read/write ratio with raid 5 (just an example). If these were 500GB and now you opt for 2TB drives, if you reduce your drive count to just 5 of these (plus 1 hotspare (drive 6)), you'd only have a performance potential of ~283 iops (using the same numbers). For this reason it would be helpful if you could provide your IOPS (average and maybe a 95% and 99% max) and the read/write ratio. This could help me provide feedback into what kind of drives to get and how many. Storage space should be considered a secondary concern (i.e. first look for your performance needs and then for your storage needs when budgeting/purchasing).

    Member since 2003

  • Thanks for the reply.  This is exactly what we're looking at.  I do have some follow up question though:

    Dev Mgr

    2. Migrating this will require full downtime and may require a full backup and restore of your SQL DB. Installing the MD3200-series failover software will most likely break Powerpath (I assume this is installed on both your servers for the connectivity to the AX150i). For this reason you would need to uninstall Powerpath prior to installing MDSM (Modular Disk Storage Manager (the MD's management and host (failover) software)). When you uninstall Powerpath you could lose disk access to your AX150i's storage. It's possible that if you are only using a single connection from each server to the AX150i that you could be running without Powerpath (or that it would work fine after uninstalling).

    3. The AX150i only supported 7200rpm SATA drives. The MD3200 only supports SAS drives. These can be 7200rpm (called Near-line SAS), 10k or 15k rpm drives. Even if performance never was an issue, don't assume that you can just go with fewer larger drives (of the same speed) and expect the same performance. A 7200rpm drive can yield about 80 iops in maximum performance potential. If you had 11 drives in a raid 5 or so (1 hotspare), you had a max performance potential of ~623 iops at a 90/10 read/write ratio with raid 5 (just an example). If these were 500GB and now you opt for 2TB drives, if you reduce your drive count to just 5 of these (plus 1 hotspare (drive 6)), you'd only have a performance potential of ~283 iops (using the same numbers). For this reason it would be helpful if you could provide your IOPS (average and maybe a 95% and 99% max) and the read/write ratio. This could help me provide feedback into what kind of drives to get and how many. Storage space should be considered a secondary concern (i.e. first look for your performance needs and then for your storage needs when budgeting/purchasing).

    I was really hoping that we wont have to lose access to the AX150i at the same time when we add the MD3220.  But it'll probably be just as easy to do a full backup of all the databases and then moved them all to another management server that we have (not part of the cluster).  Bigger question though is right now, the EMC is configured as 2 virtual RAID Array plus 1 Hot Spare - RAID 10 for Databases and a RAID 5 for temp and for our heart beat drive.  So if we need to break Powerpath, how or better yet, where would the heart beat drive go to after the change over?

    As for the new HDDs, we were planning on going with 10k RPM drives with similar break up of 2 virtual RAID of RAID 10 and another RAID 5 configurations (looking at getting all the same 300GB or the 600GB 10k RPM ones).  The other question I have are how many Hot Spare can we set up in the MD3220?  We would set aside at least 2 or more Hot Spares and perhaps even some COLD spares around.

    Thanks for your quick response.