DES-1423 exam

Home » DES-1423 exam

What should be considered?

Leave a comment

A company has a 4-node Isilon H600 cluster dedicated for a high-performance workflow. The administrator wants to convert their cluster SSD strategy from L3 cache to use the SSDs for metadata acceleration.

What should be considered?
A . Migration of data and metadata from the SSDs to HDDs can take hours.
B . Once enabled, the L3 cache cannot be disabled without support assistance.
C . Converting to use SSDs for metadata acceleration turns off prefetching.
D . Deselecting L3 cache for an SSD strategy has no impact to the workflow.

Answer: A

Explanation:

Reference: https://technodocbox.com/69495789-Databases/Storage-tiering-with-dell-emc-isilon­smartpools.html

When reviewing the actual protection output of N+4/2, what does the number “4” represent?

Leave a comment

When reviewing the actual protection output of N+4/2, what does the number “4” represent?
A . FEC stripe units per stripe
B . Hard drives used per stripe
C . Volume stripes per file system
D . FEC stripe units per file system

Answer: A

Explanation:

It’s OneFS FEC protection nomenclature for our "hybrid" protection polices. More generally, it’s written as: N+M/b where "N" is the number of data stripe units in a stripe, "M" is the number of FEC stripe units in a stripe, and "b" is the number of stripe units in a stripe which are allowed to reside on the same node.

Reference: https://www.dell.com/community/Isilon/Isi-get-output/td-p/7085467

In Isilon OneFS, what is a characteristic of CoW with snapshots?

Leave a comment

In Isilon OneFS, what is a characteristic of CoW with snapshots?
A . Used for small changes, inodes, and directories.
B . Avoids the double write penalty.
C . Increases file fragmentation.
D . Used for more substantial changes such as deletes.

Answer: A

Explanation:

With copy on write, as the name suggests, a new write to HEAD results in the old blocks being copied out to the snapshot version first. Although this incurs a double write penalty, it results in less fragmentation of the HEAD file, which is better for cache prefetch, etc. Typically, CoW is most prevalent in OneFS and is primarily used for small changes, inodes and directories.

Reference: https://www.dellemc.com/resources/en-us/asset/white-papers/products/storage/h15048-wp­next-gen-data-protection-snapshot-iq.pdf

What impact can obsolete drive firmware have on an Isilon cluster?

Leave a comment

What impact can obsolete drive firmware have on an Isilon cluster?
A . Reduces administrative overhead and increases performance.
B . Affects redundancy settings and FEC coding.
C . Affects cluster performance or hardware reliability.
D . Increases runtime and cluster performance.

Answer: C

Explanation:

Reference: http://doc.isilon.com/onefs/7.2.0/help/en-us/GUID-398C2422-1CA5-4AE0-8F3D­09F589C82E6E.html