Ask the Experts

Ask the Experts

• Star schema vs snowflake schema: Which is better?

  Yahoo’s data and business intelligence architect, Rohit Chatter, answers the latest debate, Star versus Snowflake schema, by breaking down the differences, one aspect at a time  Continue Reading

• Backup deduplication process: Target vs source deduplication

  If you’re thinking about implementing a backup deduplication process, read about the key factors to consider when deciding between target and source deduplication.  Continue Reading

• Securing big data: Architecture tips for building security in

  Expert Matt Pascucci advises a reader on securing big data with tips for building security into enterprise big data architectures.  Continue Reading

• Techniques for preventing a brute force login attack

  A brute force login attack can enable an attacker to log in to an application and steal data. Rob Shapland explains how to prevent brute force attacks.  Continue Reading

• File upload security best practices: Block a malicious file upload

  Do your Web app users upload files to your servers? Find out the dangers of malicious file uploads and learn six steps to stop file-upload attacks.  Continue Reading

• Can Hadoop tools ease the brain pain?

  Hadoop tools vendors stress that they can help you to make your data and reporting issues vanish. Know how true this claim is.  Continue Reading

• Session fixation protection: How to stop session fixation attacks

  Session fixation attacks rely on poorly managed Web application cookies. Rob Shapland answers a reader’s question on session fixation protection.  Continue Reading

• The reasons for missing hard drive space on storage arrays

  If you installed disk and didn’t get the capacity you expected, the missing hard drive space can be a result of operating system calculations, formatting, RAID and use of hot spares.  Continue Reading

• What to consider when moving to a flat network topology

  In this guide, learn what to consider when switching from a three-tier network to a flat network topology model, including virtual cluster switching and network fabrics.  Continue Reading

• Adding an old hard drive to RAID sets on servers

  When adding an old hard drive to RAID sets on servers, it’s important to account for factors such as the number of drive bays in the host. See how to configure the drives to the appropriate RAID format for the workload.  Continue Reading

• KPI formation for CDI efforts

  A KPI can help stay on track when assessing any project. Let’s take a look at what are the top three KPIs for a CDI effort.  Continue Reading

• Data quality improvement questions answered

  Data quality is the key that can open the door to reliable and intelligent reports. Learn how to improve data quality easily and effectively.  Continue Reading

• Open source databases: Top challenges to deal with

  Open source databases offer plenty of benefits. But watch out for these hassles; open source databases can be a two-sided sword.  Continue Reading

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  summary text for test CW eoc answer.  Continue Reading

• Backup vs replication: Comparing reliability

  Learn about the reliability of backup vs replication technologies, the strengths and weaknesses of each type of data protection, and what factors can affect their reliability.  Continue Reading

• BI users: More the merrier? Well, not exactly!

  Having many BI users may help you bag the best possible deal. But meeting the needs of the a few BI power users may be easier. Find out how and why.  Continue Reading

• Decoding BI 3.0

  Is BI 3.0 like the Xbox when the older versions are like Atari? Here’s a lowdown on what BI 3.0 truly stands for.  Continue Reading

• Are data analytics techniques dynamic enough for big data?

  Data analytics techniques are in the limelight. Are they a channel to make sense of big data? Get an answer from Yahoo! expert on data analytics techniques.  Continue Reading

• Fibre Channel over IP: What it is and what it’s used for

  Fibre Channel over IP bundles Fibre Channel frames into IP packets and can be a cost-sensitive solution to link remote fabrics where no dark fibre exists between sites.  Continue Reading

• Data analysis, how to get started

  How and when does an organization get started with data analysis? Should it reach a certain maturity level to implement data analysis?  Continue Reading

• Key steps for a successful SAN migration

  For a successful SAN migration, it’s key to understand your current environment and the future state of the SAN, as well as to carry out a testing phase against each platform and migration strategy.  Continue Reading

• Choosing a RAID level depends on capacity needs and data criticality

  In this Ask the Expert, Steve Pinder talks about which RAID level to choose, depending on the criticality of your data or the capacity required.  Continue Reading

• Planning a NAS migration project

  NAS migration requires careful planning around the needs of your organization. In this Ask the Expert, find out which approach to use for an effective migration.  Continue Reading

• FATA disk vs Fibre Channel for Exchange and SQL workloads

  Learn about the differences between a FATA disk and a Fibre Channel drive, and find out how to determine which drive type is better for Exchange 2007 and SQL.  Continue Reading

• RAID 5 explained: Sharing a 10 MB file among 5 drives

  Find out how RAID 5 handles sharing data shares data in a 10 MB file among five drives, including how striping and parity data figure into the equation.  Continue Reading

• Synchronous vs asynchronous replication: Order of events during data writes

  Learn about the order of events during data writes in synchronous vs asynchronous replication.  Continue Reading

• How to set up a Dell EqualLogic configuration in a VMware environment

  Find out what the key steps are for setting up a Dell EqualLogic configuration for an iSCSI SAN in a VMware virtual server environment.  Continue Reading

• Is SAN maintenance easier with virtualised servers than in a physical server setup?

  Find out how SAN maintenance differs in a virtual server environment compared with a traditional, physical server environment.  Continue Reading

• SAN troubleshooting: What are the key steps and best practices when troubleshooting a SAN?

  Learn which tools you need to perform SAN troubleshooting, which metrics point to a sign of trouble, and why granular and regular data collection is important.  Continue Reading

• How does the RAID 5 calculation work?

  Learn how to determine how much capacity you'll have in a RAID 5 drive configuration.  Continue Reading

• What does the parity bit do in RAID?

  Find out how the use of a parity bit protects RAID groups and how it's used as a method for error detection.  Continue Reading

• RAID 4 vs RAID 5: Which one costs more to implement?

  RAID 4 vs RAID 5: Which one costs more to implement? RAID 4 uses a dedicated parity disk while RAID 5 distributes parity data across all drives in the RAID set.  Continue Reading

• Backup Exec problem with external disk target: Why won't it recognise it?

  Find out how to troubleshoot a problem with Backup Exec not recognising an external disk target.  Continue Reading

• Hitachi replication: How do you do replication for HDS arrays?

  Hitachi replication: Find out how to do replication for HDS arrays, as well as which replication method is best suited for AIX servers.  Continue Reading

• Backup best practices: Is it best to use a dedicated backup server or a shared server that also runs

  Backup servers are responsible for scheduling thousands of backup jobs per day and committing thousands of associated backup details to the database. Here are some best practices for dealing with backup servers.  Continue Reading

• Dynamic code analysis vs. static analysis source code testing

  Managing vulnerabilities involves a wide array of security testing, including both dynamic and static source code analysis. Learn how the two differ, as well as how they are performed in this expert response.  Continue Reading

• How to include data governance in an MDM development process

  Learn how to include data policies and data governance in a master data management (MDM) development process even if your company doesn’t want to fund data governance.  Continue Reading

• Business intelligence tools: Choosing the right BI product

  There are loads of business intelligence tools out there on the market today. Our business intelligence expert provides some valuable resources for choosing the right BI product.  Continue Reading

• Should we buy data quality management tools or focus on policies?

  Looking improve your data quality? Data quality management tools might not be the best answer. Find out why.  Continue Reading

• RAID 5 recovery: What is the maximum number of physical drives in a RAID 5 configuration?

  Adding drives to a RAID 5 set increases your ROI and the likelihood of simultaneous drive failures, and lengthens RAID rebuild times. So what should be your physical drive limit?  Continue Reading

• Do all drives in a RAID 10 array need to be the same specification?

  We tell you the one requirement when matching drive specs in a RAID 10 array. But will mixing drives of various performance levels compromise your RAID level?  Continue Reading

• RAID 10 vs RAID 50: What is the best way to configure a storage array with 16 1 TB drives?

  Learn the characteristics of RAID 10 and RAID 50, as well as which RAID level is appropriate for your applications. I/O and protection needs contribute to your RAID choice.  Continue Reading

• Thin provisioning: Over-allocation, wide striping, space reclamation

  Learn how the three main advantages of thin provisioning -- over-allocation, wide striping and space reclamation -- can help you make the most of your storage.  Continue Reading

• SAN vs. DAS: Which is better in terms of performance and scalability?

  Is SAN or DAS better in terms of performance and scalability? Learn why the server configuration you want to support plays such a big role in your decision.  Continue Reading

• Virtual server backup: image-level backup and file-level backup

  Virtual server backup involves two types of backup: image-level backup and file-level backup. Learn the differences between them, and the limitations of file-level backup.  Continue Reading

• Data deduplication or tape archive for reducing data on disk?

  Data deduplication can reduce data stored on disk, but you'll probably need a tape archive for data with long retention requirements.  Continue Reading

• Remote data backup service guidelines

  My business needs to back up roughly 2 TB of data a night from its primary storage environment and secondary data centre. Would using a remote data backup service be an effective option?  Continue Reading

• Data deduplication technology considerations for ROBOs

  Data deduplication technology can help remote offices and branch offices (ROBOs) address bandwidth restrictions. Learn the factors to consider before adopting data deduplication technology.  Continue Reading

• Using RAID 1 and RAID 5 in a virtual server environment

  We tell you the pros and cons of using RAID 1 and RAID 5 for your OS and applications in a virtual server environment. Data protection and recovery are factors to consider.  Continue Reading

• Using data deduplication for virtual machine backup

  Deduplication can reduce data volumes during virtual machine backup. But you'll need a VM backup strategy to protect data dedupe indexes and complete your data restoration.  Continue Reading

• Choosing a data deduplication product for your data storage environment

  We tell you the three questions you should answer before choosing a data deduplication product.  Continue Reading

• LUN masking or LUN zoning: Which one is a better fit for a SAN fabric?

  GlassHouse Technologies' Steve Pinder weighs the pros and cons of using LUN masking and LUN zoning in SAN fabrics, switches and HBA configurations.  Continue Reading

• SAN purchase factors include cloud storage and I/O performance

  We outline the factors to consider when making a SAN purchase, including cloud storage, data migration, I/O performance and maintenance issues.  Continue Reading

• Fibre Channel SAN zoning: Pros and cons of WWN zoning and port zoning

  Learn the difference between World Wide Name zoning (WWN zoning) and port zoning, as well as the pros and cons of each on a Fibre Channel storage-area network (Fibre Channel SAN).  Continue Reading

• What are the key shared storage options available to SMBs/SMEs for document management?

  Learn how an iSCSI SAN and open source products can become effective shared storage options for SMBs/SMEs undertaking a document management project.  Continue Reading

• Storage-area network (SAN) fabrics: Mesh versus core-edge topology

  When designing a storage-area network (SAN) fabric, it is important to examine both mesh and core-edge SAN topologies. Learn about the pros and cons of both topologies for designing SAN fabrics and which choice is best suited for small- and ...  Continue Reading

• How to calculate the optimum fan-out ratio on a storage-area network (SAN) array

  Learn how to calculate the optimum fan-out ratio –- number of hosts connected to a port -- for a SAN array hosted in your enterprise data storage infrastructure.  Continue Reading

• What are the main steps when configuring a storage-area network (SAN) switch?

  Learn how to perform a storage-area network (SAN) switch configuration by determining the required port speed and topology, and configuring zones so devices can communicate with each other.  Continue Reading

• Achieving concurrent write access to a storage-area network (SAN) without corruption

  A business has two load-balanced Web servers accessing the same LUN of a storage-area network. Steve Pinder tells them how to achieve concurrent write access without corruption.  Continue Reading

• What are the key steps in designing and purchasing a shared storage subsystem?

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• What are some best practices for storing backup tapes offsite?

  Shipping tapes offsite? Learn the importance of recovery time objectives and recovery point objectives, inventory lists and migrating media to newer technology.  Continue Reading

• Key steps in purchasing/implementing a shared data storage subsystem

  Learn how to move from legacy direct-attached storage (DAS) and network-attached storage (NAS) boxes to an up-to-date data storage infrastructure.  Continue Reading

• What type of data storage media is best for data with long retention requirements?

  Learn what types of data storage technologies, including SATA, MAID, virtual tape libraries (VTLs) and tape drives, are best suited for data with long retention requirements.  Continue Reading

• Can I restore backup copies made from data deduplication for disaster recovery?

  For disaster recovery, you can restore backup copies made from data deduplication. However, it is crucial to protect your deduplication indexes and to restore everything in the right order.  Continue Reading

• What causes slow data backups and how can you make your backup environment more efficient?

  GlassHouse UK consultant Hywel Matthews says slow data backups -- caused by either the size of the backup pipe or the flow of the backup data -- can be addressed with various backup agents, data deduplication products, and more.  Continue Reading

• How can I merge SAN fabrics with SAN switches from different vendors?

  The Fabric Shortest Path First (FSFP) routing protocol will help you merge storage-area network (SAN) fabrics with switches from different vendors.  Continue Reading

• What data backup methods are key for a server virtualisation project?

  Server virtualisation can reduce expenditures, but introduce new complexities when it comes to data backup. Here are the points to address when implementing server virtualisation.  Continue Reading

• How to integrate data backup storage environments following a business acquisition

  Before integrating data backup environments, assess your recovery point objectives and recovery time objectives, perform a gap analysis and look at the longevity of each product.  Continue Reading

• Is continuous data protection effective enough to be the only full data copy for disaster recovery?

  CDP is effective against physical corruptions because it maintains one or more copies of your data, either locally or remotely, to ensure disaster recovery in the event of physical failure.  Continue Reading

• Recovering from a two-drive failure in a RAID 10 configuration

  In a RAID 10 configuration with four drives, data can be recovered if two of the drives fail. But recovering the data depends on which drives in the RAID configuration fail.  Continue Reading

• How does data deduplication impact backup?

  Deduplication means less data in backup storage, which means backup targets occupy less space and save on power and cooling. But dedupe at the source has a processing overhead.  Continue Reading

• How to choose the right RAID configuration for a new storage-area network (SAN)

  Before choosing a RAID configuration for a new storage-area network (SAN), you need to consider the performance requirements of your data and the number of disks needed for an effective implementation.  Continue Reading

• What makes a fabric port change to a loop port?

  If ports in your storage-area network switch are changing without updates, you need to examine the fabric device and loop device, and check to see if any drives may have been improperly connected.  Continue Reading

• When is the right time to switch from tape to disk-based backup?

  Before moving from tape to disk-based backups, you need to consider recovery objectives, the age of your current tape investment, backup and restore performance, and data protection.  Continue Reading

• RAID 10 vs. RAID 1: Mirrored drives matter

  While RAID 10 and RAID 1 are both mirroring technologies that utilise half the available drives for data, a crucial difference is the number of drives they can use in a RAID group.  Continue Reading

• Is data deduplication a good way to cut backup times from remote offices?

  Greg Gawthorpe, technical operations manager at CMC Markets, says data deduplication can be expensive, so try real-time replication as an alternative.  Continue Reading

• RAID 10: How many disk drives should you use?

  The minimum number of drives required for RAID 10 is four. RAID 10 should not be confused with RAID 0+1, which involves creating two RAID 0 stripe sets and then mirroring them.  Continue Reading

• Can replication and CDP replace a traditional backup regime?

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• How do you defragment NAS?

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• Active-active array vs active-passive array: Storage arrays explained

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• Do I need to intervene when manually updating apps replicated as part of a DR plan?

  When I'm manually updating production servers and applications replicated as a part of a disaster recovery (DR) plan, do I need to do any manual intervention to apply the updates to DR?  Continue Reading

• Can I monitor and manage a calculated RPO and RTO?

  Data backup expert W. Curtis Preston answers this question about monitoring a calculated recovery point objective (RPO) and recovery time objective (RTO).  Continue Reading

• How do you calculate the space available when you configure three disks of different capacity to RAI

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• What type of server would have the capacity to service an office of 50 people?

  If you're thinking about housing a backup server in a small office/home office (SOHO) environment, make sure backups are automated and consider backup to the cloud.  Continue Reading

• Should RAID 5 configurations include different disk volumes?

  Steve Pinder at GlassHouse Technologies (UK) Ltd, answers this question from a SearchStorage.co.UK reader regarding RAID 5 configurations: I have a server with four drives and I want to install a RAID 5 configuration. Do I need to keep one disk at a...  Continue Reading

• What is a LUN and why do we need storage LUNs?

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• Fibre Channel compared to FATA drives

  We want to buy an array for SQL and Exchange data. The vendor recommends their Fibre Channel (FC) drives, but they also have Fibre Attached Technology Adapted (FATA) drives that are about half the price. We could run twice as many FATA spindles for ...  Continue Reading

• RAID 5 configuration: How to calculate disk space for data storage and parity storage

  Find out how to calculate the disk space available for data storage and how much disk space is utilised for parity storage in a RAID 5 configuration.  Continue Reading

• Can I use a PC server as a NAS device?

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• NAS Backup: What are my options?

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• RAID 1 vs RAID 5: What are the pros and cons?

  What are the pros and cons of the mirrored disk sets of RAID 1 and the parity disk protection of RAID 5?  Continue Reading

• Can I connect datacentres 70km apart using DWDM?

  I am planning to connect two data centres by dense wavelength division multiplexing (DWDM), and the distance between them is 70 kilometres. I am also planning to buy an EMC Symmetrix box and would like to have synchronous replication for 20% of my ...  Continue Reading

• Which RAID type is optimal for a Lotus Notes server? Also what is RAID-5E?

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• Managing offsite backup tape storage: How far away should tapes be stored?

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• How would you recover Exchange Server 2003 when the log file is corrupted?

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• What are the pros and cons of inline and post process data deduplication?

  Chris Reid, consultant with Morse, looks at the pros and cons of inline and post-process data deduplication.  Continue Reading

• How can I replicate an Oracle database every five minutes between two servers each with RAID 5?

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• Agent-based and agentless replication - what are the pros and cons?

  Agent-based and agentless replication - what are the pros and cons?  Continue Reading

• What storage media can compete with tape for long-term storage?

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• Off site backup suppliers - how do you choose the most suitable for your business?

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