Questions and Answers from Accelerate with ATS: SVC/Storwize Family IP replication 25 th March 2014

Transcription

1 Q: does 5639-RM7 include SANSlide and GM-CV? A: Yes Q: how the system handle network congestion if both links of 1G use one 1G WAN link A: Network must be stale or you would have problems. Q: Any specific reason of using GMCV as preferred option? A: Yes, because it is generally used in lower BW environments. IP replication would be used in lower bandwidth environments as well. Q: Do we need to have different IP address on each port in same port group? if so, then how does port failover works with different IP in same port group? A: Yes the system handles the failover Q: Can I use Flex V7K and V7K for IP replication? A: Yes. Q: Flex V7K has only 1 port available ( for management ) if there is only 1 Gb ports. No possible select another port.. A: You cannot use the management port on the Flex V7K for replication. Q: Whitepaper for IP replication is here: ibm.com/partnerworld/wps/servlet/download/DownloadServlet?id=ufNH_KU7b6OiPCA$cnt&attach mentname=ip_partnership_evaluation_guide.pdf&token=mtm5ntc2nzu2mdg3ma==&locale=en_all_ ZZ Q: Will the recording of this webinar be available later? This is really good information that I want to share with coworkers. A: Yes the recording will be available and will be posted on our blog: A: Yes, it will be available within 24 hours at the following: IBMers - b rands,b8s00 clientset,ia IBM Business Partners - Q: what are the sizing guidelines then when there is more parallelism with the GM optimization? A: Look to the chart of maximum throughput. If you need more, then IP replication may not be an option for you.

2 Q: Does this also boost the FCIP replication or is it IP only? A: It is IP only. Both FCIP and IP links between the same to systems is not supported. Q: But -sync can only be used if no data changed during the break? A: Yes. That is correct. Q: Is there any way to calculate cluster throughput potential given various latency and bandwidth inputs? A: Bill has some charts in the deck regarding this. Q: Or is that what Group 1 / Group 2 is for? A: That is what your port groups are for. Q: lower bandwidth or higher latency, right? A: Yes. Q: DOes the IP replication functionality do any compression? A: No. It optimizes the link, but does no compression. Q: So all the network interfaces on side A need to see all interfaces on side B? A: They do not have to. Only the ports that need to talk. Q: Is there any metering on rcbuffersize that can be viewed by the customer using either TPC or direct commands? A: No. You would need to engage support. Q: I need more throughput on my FCIP replication. Is any of this technology going to help that? A: You would hvae to look to 3rd parties for that. You need to make sure whatever you use is approve for use with IP replication. Q: But FC replication doesn't give me the speed boost so I'm limited in my throughput at high latency distances. A: Potentially, yes. Plan your scenario. Q: does rcbuffersize affect throughput? Is it safe to increase that at the target cluster? A: Usually you only increase that on the recommendation of support. Usually you are not going to overrun it with the maximum that IP based replication can do. Q: You didn't take the iscsi off that node 2 port 1 link A: You don't have to. It is recommended that it is dedicated to replication, but you can do ISCSI and replication over the same ports. Q: Is the unified v7000 different than the Storwize for what mode it is in? A: This is block replication. The Unified can do file replications (which we are not talking about) and block replciation. IP replication could do the block portion of the Unifed replication. Q: Is that 1Mbps bidirectional on the inter-cluster link? A: Yes. It is bi-directional

3 Q: Can the two sites be using the data at the same time or one can be productive and the other should be just for DRP & BC A: Using remote mirror, only 1 site can use the data. Unsing SVC Stretched cluster, both sides can use the data simultaneously. Q: What does sanslide buy v7k over tcp windowsize on netapp, they both seem to accomplish the same thing, hide network latency. A: I cannot comment on the NetApp application. We optimze the link. We do not "hide" latency. The latency is what it is. We make the latency more tolerable by using virtual connections within the link to do parallelism on the link. Q: can one ip-replication target volume be the source of another fc-replication source volume at the same time? just like DS8K MGM solution A: No Q: GMCV is only pushing block level changes across the IP replication? A: Any of your mirroring in this scenario are block level changes. Q: When using the PureFlex Server solution, with it's Flex Manager Suite - does it integrate into the SVC / Storwize tools directly? A: You can get to the management interface from the Flexsystem manager. Q: Can you throttle the IP replication traffic? A: Yes. You can throttle the traffice with the Link Bandwidth setting. Bill will get to that. Q: Does the FC MM have quorum / tie breaker technology to support Metro HA clustering of applications? A: No...No quorum disk is required for Metro Mirror. In a SVC Stretched cluster scenario it is, but that is not mirroring. Q: V840 has an SVC cluster for that (replication) as a requirement correct? A: Technically, the V840 is a system of it's own, however, it does use SVC nodes. Q: Is this replication encrypted as an option? A: The software does not encrypt natively. However CHAP challenge protocols are supported. Q: Is the recovery at the other end of the replication only crash consistent or do you offer snap-shot integration into the filesystems and applications for quiesce of i/o during snapshot? A: So in all our replication scenarios, it would be crash consistent unless you use FlashCopy manager or script something that would be application consistent. Q: How do we get a copy of the presentation? A: Please visit: A: Presentation and replays are all posted on the Accelerate with ATS Blog:

4 Q: per earlier question, there is no compression (or deduplication?) so based on this, it would seem you would need upwards of 4-5x the badwidth to obtain the same performance as FCIP - is this correct? A: The SANSlide sofware utilizes the piple better, so in reality we can compete with compression because we optimize the link in a parallel fashion. Q: Is the Background Copy Rate the max percent of the total bandwidth we provided? A: The background copy rate is the % of the pipe that can be used for initial sync or re-sync traffic. Q: So the "IP routing" line on the lower lefthand graph is the only window we have into SANSlide performance/activity? Should we consider SANSlide methods to be out of sight and out of mind? A: Generally, yes. Q: There is a new PING command in the CLI. Are there any other new CLI commands related to FCIP that can be useful in troubleshooting or performance reporting. A: Not that I am aware of. You have always been able to ping from the CLI (At least that I am aware of). Q: What is RPO? A: Recovery Point Objective Q: A: Thank you. Q: Background copy rate does what? A: Background copy rate is how much is dedicated to inital sync and re-sync traffic rather than normal mirroring traffic. Q: Did you post the URL for tthe blog? A: Blog here: Q: Is V7K- code stable to configure IP Replication or do we expect another release? A: is stable for IP based replication is currently out. A: Download today's presentation here - Q: what is the host resource usage when we do IP replication instead of FC replication A: Host resource. Nothing. Controller resource 20-25% CPU.

5 Q: WIth one physical link only, and 2 x V7000 in cluster. How many Port Groups need to be used? A: You only have to use 1. Q: can I use both port groups using one physical link only? A: You could, yes. I don't believe there is any restriction on that. Q: Tivoli FCM: see this link: Q: Q: So, conceptually I will use two Port Groups if I have 2 physical links. They are tied. Is it correct? A: They are not aggregated if that is what you mean. They are 2 separate links. Q: What is the distancefor 80 ms? A: For a GM scenario, 8000 km. 10ms for every 1000 km Q: can you share ethernet ports between iscsi and replication A: Yes, but it is not recommended. We recommend you dedicate ports to replication. Q: can we use the 2nd management port for replication? A: Yes Q: When changing from FC to IP replication, do you have to delete the destination volumes as well or can they be used as a seed of the data? If they must be destroyed, is there a way to seed the data? A: So. If you can tolerate an outage, you can take the system down, break the mirrors and when putting them back together us the -sync flag. Other than that, no way to preserve the data. Q: is this IP replication available on the FlashSystem V840 A: Yes Q: is this IP replication available on the FlashSystem V840 A: However, if you are replicating massive amounts of data and need to keep up wit the flash, it might not be the best. I can push more mirroring traffic with FC.

6 Q: Can I use more than one port for IP replication A: Up to 2. Bill will get to that. Q: Can I choose one 1 gb port and another 10gb port for replication A: No. They must be both 10 or both 1. Q: What is the block size used for IP replication. A: --unanswered-- Q: But in that case how would IP replication work If i am going to use FC ports A: You cannot use IP AND FC between the same 2 systems. Q: Can I do port aggregration or trunking to get a large bandwidth A: No. Port aggregation is not supported. Q: The ports 3260 and 3265 needs to be opened between source and the target V7000 systems...am I correct? A: Yes. Those are the ports. Q: What ports are used for IP replication A: You can use the 1 Gb management ports or 10Gb Ethernet ports to replicate. Q: but Storwize in replication layer can still not use iscsi target devices as back-end right? (not that i would want to). A: No. ISCSI host attach only. Q: bg copy rate is used different from other copy rate settings. This is confusing because they are called the same but mean something different. A: In 7.2 you have link bandwidth and background copy %. It helps with the confusion. Earlier versions, were, I admit confusing. Q: I understand, but everywhere else in StorWize copy rate 50 means 2MB/s, where it here means 50% of the bandwidth. A: Understood. Q: Another Recovery question. On a T3 recovery, the ClusterID changes, rendering all replication relationships invalid and destroying the cluster partnerships. Do you know if anything changed in this field with 7.2? A: I am aware of nothing that has changed with this. Q: where is this available? a certain model type or code level or both? A: Code level 7.2 and beyond. All Storwize family models included. Q: FCIP routers pprovide compression and help save on bandwidth. When should one go for IP based replication against FCIP based replication. A: Usually IP replication should be used when you can tolerate the speed restrictions. For higher bandwidth scenarios, use FC with FCIP

7 Q: Regarding the performance limits of the 10 Gbit/s ports, what is currently the bottleneck? CPU time? SANSlide code? A: CPU is currently the bottleneck. Q: Global Mirror with Change Volumes traffic is always considered "background copy," correct? A: Yes. You are correct. So if using GMCV only, you could set the Background copy % to 100. Q: Will the replication coexist with Riverbed? A: I would suggest a SCOR (RPQ) in that scenario. There have been some problems with using IP replication with Riverbed and some other WAN optimizers. Q: what should be the dedicated ports for replication? A: Usually if you are going to be doing lots of replication, we recommend that you dedicate Fibre Channel ports to it to minimize potential for problems. Q: any ports from any controlar? A: Any port from any controller.