Free E20-335 Exam Dumps Preview

Explanation:

For consistent activation, there should be a control host with access to only Gatekeeper (GK) devices, or a separate HBA on the production host with access only to GKs and not data devices. This is to ensure that in write intensive environments SYMAPI will be able to freeze and then thaw I/O to the production devices within the ECA window, regardless of the number of outstanding I/Os held by the host HBA accessing the data devices.
BCM

Explanation:

A FAST policy groups between one and three tiers and assigns an upper usage limit for each Symmetrix tier.

The upper limit specifies how much capacity of a storage group associated with the policy can reside on that particular Symmetrix tier.
FAST policies may include storage tiers of only one type disk group provisioning (DP) or virtual provisioning (VP). The first tier added to a policy will determine the type of tiers that can subsequently be added.

The usage limit for each tier must be between 1 percent and 100 percent. When combined, the upper usage limit for all thin storage tiers in the policy must total at least 100 percent, but may be greater than 100 percent.

Creating a policy with a total upper usage limit greater than 100 percent allows flexibility with the configuration of a storage group whereby data may be moved between tiers without necessarily having to move a corresponding amount of other data within the same storage group. Multiple FAST policies may reuse the same tier, allowing different usage limits to be applied to different storage groups for the same tier.
A Symmetrix VMAX storage array will support up to 256 FAST policies. Each FAST policy name may be up to 32 alpha-numeric characters, hyphens (-), and underscores (_). Policy names are not case-sensitive.

Explanation:

The symclone create action defines the clone copy session requirements and sets the track protection bitmap on the source device to detect which tracks are being accessed by the target host or written to by the source host. The target device is made Not Ready to its host and placed on hold status for clone copy session activity.
This prevents other control operations from using the device. The clone copy does not become accessible to its host until the copy session is activated. The output has been edited to fit the slide. Note that the target devices have been moved to a Not Ready state (NR) upon Clone session creation. They will be in a held state until the Clone session is terminated.

Explanation:

Delta Set Extension (DSE), extends the cache space available for SRDF/A session cycles by off loading some or all of its cycle data from cache to preconfigured disk storage, or pools, which are similar to SAVE device pools.
BCM

Explanation:

Each Symmetrix logical volume is allowed up to 4 mirrors. Prior to Enginuity 5874, local mirrors and parity RAID mirrors would occupy a second mirror position.
This limited the number of remote mirrors and TimeFinder/Mirror BCVs these volumes could be joined to. Starting with Enginuity 5874, RAID virtual architecture (RVA) virtualizes mirror positions. This means that backend management of RAID groups is hidden from rest of Enginuity. Remote mirrors still occupy a mirror position but local mirrors no longer occupy a mirror position irrespective of their protection type. Also, TimeFinder/Mirror was discontinued and replaced with TimeFinder/Clone starting 5874. Thus the 4 mirror limit is no longer a limiting factor

Explanation:

Throttling allows users to limit SAN bandwidth usage by Open Replicator. If left unchecked, Open Replicator consumes the full bandwidth of the SAN. It performs very fast, which could be a problem if the SAN is being shared by hosts performing I/O to the local volumes on the Controlling Array.
Pace values range from zero (0) to nine (9). A pace of zero (0) means that the session is not throttled at all.
The default pace for an Open Replicator session is five (5). Ceiling values range from zero percent (0%) to one hundred percent (100%). A zero percent (0%) setting on the port indicates the port will not be used for Open Replicator. A one hundred percent (100%) setting on the port allows Open Replicator full bandwidth usage, if necessary. The default ceiling value is None, which means that an Open Replicator session will be regulated by the Pace setting.
OR-FLM

Explanation:

The min_auto_meta_size specifies the size threshold that triggers auto meta creation. When users try to create a device greater than min_auto_meta_size, and auto_meta is enabled, a meta will be created.
SCM

Explanation:

RAID 5 is based on the industry standard algorithm and can be configured with three data and one parity, or seven data and one parity. While the latter will provide more capacity per $, there is a greater performance impact when in degraded mode where a drive has failed and all surviving drives must be read in order to rebuild the missing data.

RAID 6 is focused on availability. With the new larger capacity disk drives, rebuild times may take multiple days increasing the exposure to a second disk failure.

Random read performance is similar across all protection types, assuming you are comparing the same number of drives. The major difference is write performance. With mirrored devices for every host write there are two writes on the backend. With RAID 5, each host write results in two reads and two writes. For RAID 6, each host write results in three reads and three writes. Other data protection schemes include remote replication using SRDF.
SCM

Explanation:

The Config Manager architecture allows it to run Symwin scripts on the Symmetrix service processor.

Configuration change requests are generated either by the symconfigure SYMCLI command or a SYMAPI library call generated by a user making a request through the Symmetrix Management Console (SMC) GUI.
These requests are converted by SYMAPI on the host to Symmetrix syscalls and transmitted to the Symmetrix through the channel interconnect. The Symmetrix front end routes the requests to the service processor, which invokes Symmwin procedures to perform the requested changes to the Symmetrix.

Since these scripts are the same ones that a Customer Services Engineer would employ to configure the Symmetrix, Config Manager is able to do almost everything that is possible through Symwin scripts.

Explanation:

With the new feature, A > B, and B > C can be simultaneously in a Pre Copy mode. So data can flow from A > B and then on from B > C. Hence the term
Cascaded TimeFinder/Clone. When both clone sessions have completed one precopy cycle, A > B can be activated. After A > B reach the copied state, B > C session can be activated.
BCM

Explanation:

There are two types of Symmetrix tiers: dynamic and static. A dynamic tier automatically includes all disk groups currently in the array that match the tier technology. This type of tier will expand to accommodate any newly added disk groups.

Dynamic tiers are easy to set up and involve less management overhead but since it allows disk groups of varying speeds to be part of a tier, it is difficult to get predictable performance from a particular tier.

Static tiers allow for better performance predictability as a result of FAST moves and are preferable to dynamic tiers.
FAST VP cannot run on dynamic Symmetrix tiers.
SCM

Explanation:

The Open Replicator/LM license enables Hot Pull. This comes free of charge with the Symmetrix Migrator Package.
The Open Replicator/DM license enables the other three Open Replicator actions, namely, Cold Push, Cold Pull and Hot Push.
BCM

Explanation:

The recreate option is an incremental copy session. Incremental copy sessions are ONLY available for PUSH operations.

OR-FLM