Technical Interview Questions (June 2012)

on

Some random Technical Interview type questions:

Q: What is VAAI and what are its advantages?
vStorage API for Array Integration (VAAI) is an application program interface (API) framework from VMware that enables certain storage tasks, such as thin provisioning, to be offloaded from the VMware server virtualization hardware to the storage array.
Offloading these tasks lessens the processing workload on the virtual server hardware. For a storage administrator to make use of VAAI, the manufacturer of his storage system must have built support for VAAI into the storage system.
Introduced in vSphere 4 with support for block-based (Fibre Channel or iSCSI) storage systems, VAAI consisted of a number of primitives, or parts. “Copy offload” enables the storage system to make full copies of data within the array, offloading that chore from the ESX server. “Write same offload” enables the storage system to zero out a large number of data blocks to speed the provisioning of virtual machines (VMs) and reduce I/O. Hardware-assisted locking allows vCenter to offload SCSI commands from the ESX server to the storage system so the array can control the locking mechanism while the system does data updates.
In vSphere 5, vStorage APIs for Array Integration were enhanced. The most notable new functionality addresses thin provisioning of storage systems and expands support to network-attached storage (NAS) devices.

Q: What is VASA?
vStorage APIs for Storage Awareness (VASA) is a set of application program interfaces (APIs) that enables vSphere vCenter to recognize the capabilities of storage arrays. Such capabilities, including RAID, native thin provisioning and deduplication, are made visible within vCenter. This visibility makes it easier for virtualization and storage administrators to make decisions about how data stores should be maintained -- for example, choosing which disk should host a particular virtual machine (VM).
VASA also provides information about storage arrays to vSphere’s Profile-Driven Storage feature, which determines whether the device a VM is stored on complies with the VM’s storage requirements. In addition, VASA provides VMware vSphere’s Storage Distributed Resource Scheduler (DRS) with information on storage arrays so that Storage DRS can work optimally with them.
VASA was released with VMware’s vSphere 5.

Q: What a major advantage of Data ONTAP 8?
You can now have 64-bit aggregates, whereas pre-DOT8 there were only 32-bit aggregates.

Q: What is the main reason to upgrade to Data ONTAP 8?
The main reason to upgrade to DOT8 is to get > 16TB volume sizes.
64-bit aggregates have a maximum size of 100TB depending on storage model.

Q: In what way is the Data ONTAP 8 code different to pre-Data ONTAP 8 code?
DOT8 has been re-written to run off FreeBSD – this is a departure from the original Berkeley Net/2 code.

Q: What is an ACP port on a NetApp FAS series controller?
ACP is an anacronym for Alternate Control Path. The ACP port is an ethernet port. Alternate Control Path (ACP) is for SAS disk shelves for out-of-band management.

Q: List the components that make up a complete VMware View solution?
VMware vSphere Infrastructre – vCenter and vSphere hosts.
View Connection Server – the connection broker.
View Transfer Server – for scenarios where offline desktops are used.
View Security Server – access gateway for secure public connections over SSL.
View Composer – for linked clones and install on the vCenter.
View Persona Management – for user profile management.

Q: Explain the time hierarchy in a Windows Domain Environment with Virtual Servers, VM Hosts and ISP?
A Virtual Server will use VM Host Time Synchronization to get time from a VM Host.
The VM Host will use NTP to get time from a Forest Root PDC.
A Physical Member Server or Client will use Windows Time to get time from a Virtual or Physical DC.
A Virtual DC can either use VM Host Time Synchronization to get time from a VM Host, or Windows Time to get time from a Forest Root PDC.
A Physical DC will use Windows Time to get time from a Forest Root PDC
Other NTP Clients will use NTP to get time from the Forest Root PDC.
A Trusted Domain Forest Root PDC will use NTP to get time from the Forest Root PDC.
The Forest Root PDC will use NTP to get time from an ISP's Time Servers.
Note that time within an AD site should be accurate to within 2 seconds, and time across AD sites should be accurate to within 20 seconds.

Q: Where can you apply Group Policy objects?
Organizational Units
The Domain
Sites

Q: What is the major difference between Citrix XenApp 5 and XenApp 6?
XenApp 6 is only available for Windows 2008 R2, which uses a 64 bit architecture.

Q: What is the difference between a front-end and a back-end storage problem?
A front-end storage problem relates to problem with the interfaces – for example throughput limits being hit. A back-end storage problem relates to a problem with the internal storage hardware – disks, RAID setup etcetera – and may manifest itself as high latency and slow read/write performance.

Q: What is the database size limit with Exchange 2003?
With Microsoft Exchange Server 2003 Service Pack 2 (SP2) the database size limits for Microsoft Exchange Server 2003 Standard Edition were increased from 16 GB to 18 GB, and the limit can be increased to as much as 75 GB by using a registry key.
Microsoft Exchange Server 2003 Enterprise Edition does not have a maximum database size limit.

Q: Does read or write have a penalty with RAID 5, and why?
Writing has a penalty with RAID 5, as the parity bit needs to be calculated for every write.

Q: You have made a DNS update – how do you force the update across multiple DNS servers?
If using non-active directory integrated DNS zones then do 'update server data files.'
If these are active directory integrated zones, use AD sites and services (dssite.msc) to force replication to run now (replicate now).

Q: Is AD replication push or pull?
Pull.

Comments

Post a Comment