- How many Cache directors, Front-end directors and Back-end directors we can use in DMX-4 ?
Cache Directors = 4 Min to 8 Max.
Front-end Directors = up to 12 max.
Back-end Directors = 6 Min to 8 Max.
Back-end Directors = 6 Min to 8 Max.
- How many hypers can be created in a Single disk in DMX4?
- What is Vault drives and Hot Spare?
Hot Spare: At the time of physical drive failure hot spare drives will take place
- Can you explain about Read Hit, Read Miss and Fast Write and Delayed Write?
Read Miss: In a read miss operation, the requested data is not in global memory and must be retrieved from a disk device. While the channel director creates space in the global memory, the disk director reads the data from the disk device. The disk director stores the data in global memory and updates the directory table. The channel director then reconnects with the host and transfers the data. because the data is not in global memory, the symmetrix system must search for data on the disk and then transfer it to the channel adding seek and latency times to the operation.
Fast Write A fast write occurs when the percentage of modified data in global memory is less than the fast write threshold. On a host write command, the channel director places the incoming blocks directly into global memory. For fast write operations, the channel director stores the data in global memory and sends a “channel end” and “device end” to the host computer. The disk director then asynchronously destages the data from global memory to the disk device.
Delayed Fast Write: A delayed fast write occurs only when the fast write threshold has been exceeded. That is the percentage of global memory containing modified data is higher than the fast write threshold. If this situation occurs, the symmetrix system disconnects the channel directors from the channels. The disk director then de-stages the data to disk. When sufficient global memory space is available. The channel directors reconnect to their channels and process the fast I/O requires as a fast write. The symmectrix system continues to process read operations during delayed fast writes with sufficient global memory present, this type of global memory operation rarely occurs.
- What is the maximum hyper size in DMX-4?
Maximum Capacity = 59GB or 61425 MB
- How many members can contain in one Meta?
- How many LUN IDs available per FA port?
- What is Dynamic LUN addressing?
- What are the possible device service states and device status states?
Device Status States : Ready, Not Ready and Write Disable.
- How do you reserve the devices?
- How do you create the Disk Groups
We can rename the existing disk groups.
Example: symconfigure -sid 207 -cmd “set disk_group 4 disk_group_name = flash_dsks;” -v -nop commit
- How do you check the free space by Disk group and Array as whole?
Array as whole : Symconfigure -sid XXXX list -freespace
- How do you check the total assigned devices to a particular Host?
- How do you check the total allocated storage of a particular Host?
Thanks for Sharing ... Can you please share more questions ...
ReplyDeleteYes Sure... Give me some time... Will publish part 2 shortly..
DeleteHi Himanshu
ReplyDeleteDo you have more interview questions with answers