FAQ - ESVA 패밀리

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1. Define scale-out architecture.
   In the storage space, scale-out architecture is an architecture that allows users to increase performance and capacity in a linear manner by consolidating multiple storage systems.
2. What is the major difference between scale-up and scale-out architecture?
   In scale-up architecture, system capacity and performance are increased by replacing - replacing the smaller system with a bigger one, and replacing the slower system with a quicker one. However in scale-out architecture, system capacity and performance are increased by "adding." Capacity and performance can be linearly increased by adding new ESVA systems to the current configuration.
3. What is distributed load balancing?
   Distributed load balancing is a way to balance workloads among systems in a scale-out configuration. For example, when host issues a write request containing six data blocks to a configuration composed of three systems, each system would receive two blocks.
4. What is automatic data migration?
   Automatic data migration is a way to ensure balanced workloads among systems when the configuration changes. For example, in a configuration composed of two systems, each containing three data blocks, when a new system is added, the data will be automatically migrated to make each system contain two data blocks.
5. What host interface do ESVA products support?
   The ESVA product line supports both Fibre Channel and iSCSI host protocols. If you need Fibre Channel host storage, please select the F10, F40, F60 or F70. If you need iSCSI host storage, please select the E10 or E60.
6. Does ESVA support both FC 8Gb/s and 4Gb/s?
   Yes.
7. Are ESVA FC 8Gb/s products backward compatible with FC 4Gb/s?
   Yes, ESVA systems will auto detect the speed and are backward compatible.
8. What is "virtual pool"?
   A virtual pool is a storage pool that consolidates multiple disks through storage virtualization. The capacity of the pool can be used freely without regard to where the space physically resides. When creating a virtual pool, users can choose to protect it with the RAID level they like.
9. What is "virtual volume"?
   A virtual volume is a LUN created from the virtual pool and presented to the host. When creating the volume, users can decide to thin provision or full provision it.
10. How many ESVA systems can be consolidated in a virtual pool?
    A virtual pool can include a maximum of 12 ESVA systems.
11. How many JBODs can be attached to an ESVA system?
    A maximum of 6 JBODs can be attached to an ESVA system.
12. How many disk drives can a virtual pool include?
    A virtual pool can include a maximum of 1344 drives.
13. How many virtual pools can be managed by a master ESVA system?
    A master ESVA system can manage a maximum of 7 virtual pools.
14. How many virtual volumes can be created from a virtual pool?
    A maximum of 1024 virtual volumes can be created from a virtual pool.
15. What is the maximum size of a virtual pool?
    The maximum size of a virtual pool is 2PB.
16. What is the maximum size of a virtual volume?
    The maximum size of a virtual volume is 2PB.
17. What is the minimum size of a virtual volume?
    The minimum size of a virtual volume is 10GB.
18. Does ESVA support a CLI? If so, how can I use the CLI?
    Yes, ESVA supports CLI operations. Third party applications or scripts written by users can be used with ESVA through the CLI.
19. What is the rollback function provided by ESVA?
    Users can choose to restore a source volume back to an earlier state by rolling back to a specific snapshot image. The rollback operation will run at background. The source volume can be mapped and used by host before the operation is done.
20. How do I execute the rollback function in ESVA?
    Stop I/O on the source volume you would like to rollback, unmap its LUN mapping, and then execute the rollback with a specific snapshot image. After executing the rollback, remap the source volume to the host for I/O access.
21. What is the remote replication function provided by ESVA?
    With remote replication, users can make a volume mirror pair in different pools. The pair relationship can be set as Asynchronous or Synchronous.
22. How many source volumes for remote replication can a virtual pool include?
    A virtual pool can include a maximum of 32 source volumes for remote replication.
23. How many existing replication pair relations can a source volume keep?
    A source volume can keep a maximum of 8 existing pair relations.
24. How many existing replication pairs can a virtual pool include?
    A virtual pool can include a maximum number of 256 existing replication pairs.
25. There are multiple host ports on a ESVA system. Can I connect only some of the ports to the SAN?
    No, all host ports should be connected to the SAN. In the ESVA architecture, the bandwidth of all host ports will be utilized.
26. In remote replication, can a target volume be written, or is it read-only?
    A target volume can be mapped (after split) and used for testing, data verification and backup. But all modifications to the target volume will be erased when the pair starts to re-sync. If you want to keep the modified data on the target volume, you should stop the mirror pair, or take snapshot for the target volume.
27. When I remove capacity (whether on an ESVA system or on a JBOD), will the data be erased?
    When you remove some capacity from an ESVA virtual pool, data will be automatically migrated to and kept intact on other storage space in the pool.
28. How do I assign spare drive for a pool element?
    SANWatch automatically assigns a spare drive when a virtual pool is created or expanded.
29. How do I know the hardware status of an ESVA system?
    Open SANWatch Storage Manager , and you can see the hardware related information of the ESVA system.
30. What function does ESVA provide to help users monitor the hardware status?
    Users can monitor the hardware status of an ESVA system in two ways. They can check the status LED indicators on all main modules, or set the event notification function in SANWatch. By setting the event trigger for a specific error, users will be notified when the error happens.
31. Can I use my existing EonStor products with ESVA in any way? For example, as a data backup destination?
    No, only ESVA systems can be used in a virtualized configuration. The backup destination of an ESVA virtual volume must be another ESVA virtual volume.
32. What should I do to add a new ESVA system to an existing storage pool?
    First you should connect the cables. If you use iSCSI-host models, then you should add the IP of the new system to the iSCSI initiator as a target IP. After the manual configuration is done, data will be automatically migrated to balance the workloads across all element systems.
33. Does ESVA provide writeable snapshots?
    ESVA does not currently provide a writeable snapshot. However, a snapshot image can be used as the source of a volume copy, and a volume copy can create immediate usable data copies.
34. What performance impact does remote replication cause?
    It depends on what the host application is and the bandwidth between the source and the target volume.
35. Does ESVA support VMware?
    For the latest information on ESVA compatibility with VMware, please refer to the link: http://www.vmware.com/resources/compatibility/search.php
36. What kind of database does ESVA support?
    ESVA supports all kinds of database. ESVA also provides a flush agent on MS-SQL, Oracle, and Exchange servers to ensure the integrity of data copies.
37. Can I monitor the utilization rate of each data volume through SANWatch?
    Yes, you can see the utilization of each data volume on SANWatch GUI.
38. ESVA automatically allocates a container for snapshot images. How should I manage the capacity of the container?
    Users don't need to worry about the capacity of the container because ESVA automatically stores snapshot images in the container in an optimized way. When the container is almost full, the functions of "prune" and "purge" will remove unnecessary snapshot images.
39. After several times of deleting and adding files, is it possible that the size of differential data stored in the snapshot container becomes larger than the size of data in the source volume?
    Yes, it is possible. This may happen because the operating system does not always write data starting from the first empty block. However, the container will never be larger than the source volume.
40. What kind of spin-down technology does ESVA adopt?
    ESVA provides two levels of spin-down. The actual energy efficiency varies with the power-saving designs of drives.
41. Does ESVA support automatic failover/failback on a mirror pair?
    No, it doesn't. Replication creates data copy on the target volume. When you would like to use the copy, you only need to map the volume to the host.
42. Does SANWatch provide user login control and access control?
    SANWatch provides login control, but does not limit the access of login users.
43. Does ESVA provide 10Gb/s iSCSI solutions?
    Yes.
44. Does ESVA support solid state disks (SSD)?
    Yes.
45. If one ESVA member system suffers from power failure or cable disconnection, can I still access the storage pool?
    No, you will not be able to access the pool. In this case, you can easily regain access by re-powering on the system or re-connecting the cable.