| Question |
| Give a brief idea about Business Continuity. |
| Answer |
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| Business Continuity is the preparation for, response to, and recovery from an application outage that adversely affects business operations. |
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| Question |
| How many clone copies we can have for one std dev ? |
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| Answer |
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| 16 |
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| Question |
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| Brief concept of GOLD COPY. |
| Answer |
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| Gold copy is copy of R2 dev i.e. R2BCV |
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| Question |
| Explain what is deltaset in SRDF/A? |
| Answer |
| SRDF/A uses Delta Sets to maintain a group of writes collected over a short period of time. Delta Sets enable all of the efficiencies that SRDF/A delivers. There are four types of Delta Sets to manage the data flow process. |
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| Question |
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| What is the distance limitation for SRDF/S ? |
| Answer |
| <200 KM as per EMC |
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| Question |
| What are the different types of Front-end directors in DMX4 and the purpose of each one? |
| Answer |
| ESCON (EA) : for mainframe attachment and SRDF family links FICON (EF) : provides the industry’s highest performance connectivity Option for the mainframe. Fibre (FA/DA) : Connectivity option for open systems direct and SAN Attachment, and can be used for SRDF family remote Replication links. iSCSI (SE) : Provides the industry’s first high-end Iscsi Implementation. GigE (RE) : for SRDF family replication with compression support. |
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| Question |
| What are those four delta set avail and can you explain briefly? |
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| Answer |
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| Source side: Capture and Transmit. Target-site: Receive and Apply. |
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| Question |
| What is domino effect ? |
| Answer |
| The device domino effect mode ensures that the data on the source (R1) and target (R2)devices are always in sync. The Symmetrix array will force the source (R1) device to a Not Ready state and respond “intervention required/unit not ready†to the host whenever it detects one side in a remotely mirrored pair is unavailable, or all link failures have occurred and the host tries to access the device. It can be enabled and disbled using symcli commands |
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| Question |
| What is the best practice to change the srdf mode from adaptive copy to async mode ? |
| Answer |
| |
| When pending track count is less than 30K. |
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| Question |
| How to prioritize replication CG wise ? |
| Answer |
| You can use session priority, which by default set to 33 for all groups(can be changed by admin)range 1 to 64. highest priority being 1 and lowest being 64. highest priority session will be dropped last. |
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| Question |
| Can we take a clone copy of the R2 device while in sync with R1 ? |
| Answer |
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| yes. |
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| Question |
| |
| What is over subscription in symmetrix ? |
| Answer |
| In thin provisioning, a large amount of storage is set aside for an application, but storage is only released incrementally as additional capacity is needed. Since the application is given control of far more storage than it’s actually able to use at the moment, that total storage capacity is said to be “oversubscribed” or “overbooked”. |
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| Question |
| What is difference between domino and srdf/S modes ? |
| Answer |
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| Domino option for the mirrored pair, any failure to complete write operations to both volumes in the relationship will cause the source volume to present an intervention required status to the operating system. |
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| Question |
| What is SRDF ? |
| Answer |
| SRDF(symmetrix remote data facility) is remote replication solution provided by EMC for enterprise level storage. |
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| Question |
| What are the Benefits and Advantages of SRDF ? |
| Answer |
| Its DR solution for any disaster @ primary site so that secondary site can act as primary until original site is back online. |
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| Question |
| When data is being copied from R1 to R2 will it copy only occupied data in the disk or even the empty tracks as in full disk. ? |
| Answer |
| Data is copied at track level and its copied full initially and changes are sent to DR side thereafter. |
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| Question |
| |
| Can you please brief dynamic R1/R2 swap ? |
| Answer |
| The dynamic R1/R2 swap feature swaps the SRDF personality of the SRDF device designations of a specified device or composite group. |
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| Question |
| In reference to the above does even empty tracks in the disk are also copied. ex 60Gb is filled out of 300gb. Then will only 60 gb will be copied or entire 300gb. |
| Answer |
| Data is copied at track level and whole lun will be copied, whether it is empty or fully occupied. |
