RAID vs erasure coding for flash storage

Coding Challenge

By layering data risk management processes into your data governance framework, you can ensure the personally identifiable …

Erasure codingis a technique that uses a mathematical function to transform a set of data into a form that includes redundancy in a way that allows the original data to be recreated from a subset of the redundant pieces.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States.Privacy

Ontario Institute for Cancer Research uses open source clouds to aid cancer research

Please provide a Corporate E-mail Address.

IBM adds deduplication to Spectrum Virtualize, and Storwize arrays

Creating a digital culture is essential in the age of information, but companies must not lose sight of their core values in the …

HPE strengthened its composable infrastructure strategy with the acquisition of Plexxi, a startup that adds a networking element …

Please check the box if you want to proceed.

With the simple look of the command-line interface, organizations dont always realize the advantages it brings to systems …

This email address is already registered. Pleaselogin.

Charles Kao explains why continuous learning, observation of merit and appreciation of others are key elements for an effective …

Array-based or vSphere Replication for VMware SRM?

Erasure coding therefore provides good resiliency at the cost of performance, explaining why we have typically only seen implementations in systems such as object storage.

There are multipleRAID levelsthat encompass simple data mirroring (creating one or more images of an entire drive or group of drives) to systems that calculate recovery information known as parity that can mathematically recreate lost data in the event of a device failure.

Please check the box if you want to proceed.

I agree to my information being processed by TechTarget and itsPartnersto contact me via phone, email, or other means regarding information relevant to my professional interests. I may unsubscribe at any time.

Backup gets cloudier, edges closer to on-prem/cloud interchangeability

Erasure coding vs. RAID: Benefits and challenges

Best practice data protection strategy combinesbackup with snapshots, CDP and replicationfor different levels of recovery.

I agree to TechTargetsTerms of UsePrivacy Policy, and the transfer of my information to the United States for processing to provide me with relevant information as described in our Privacy Policy.

Case study: British Airways global B2B sales gathered under Salesforce cloud

However, we are starting to see the emergence of very large capacity flash drives (Samsung has a 16TB unit; Seagate has demonstrated a 60TB drive) and, as a result, the scaling limitations of RAID as seen in hard disk drives will start to hit flash.

Common RAID formats include RAID-5 (two or more data disks and aparitydisk in a RAID group) and RAID-6 (two or more data disks and two parity disks), the latter being used to provide higher resiliency in large capacity media devices where rebuild times can be significant. In practice, for RAID-5/6 systems, data and parity is spread across all media devices, rather than being on dedicated drives.

Its a fact of life that despite being highly reliable, flash media can go bad.

Virtual machine backup in Benelux: When to choose specialist software?

Typically, the coding technique is expressed using two numbers, one defining the number of original pieces of data and another expressing the additional redundant pieces created. For example, an erasure coding scheme could take 10 original pieces of data, transform this into 16 pieces and allow the original data to be recovered using any 10 of the 16.

With the race toward quantum computing underway, interest in post-quantum encryption is growing. ISACAs Rob Clyde explains how …

With new capabilities, the future of ADCs is bright. Learn what features this networking workhorse has acquired and what it means…

At this point, suppliers will have to look more seriously at data protection using erasure coding, and we could see some interesting developments in storage resiliency in the coming years as a result.

Read more on Data protection, backup and archiving

HP Inc results boosted by PC sales as it waits for 3D manufacturing to take off

SSD Raid 101: The essentials of flash storage and Raid

Networking pros should take a new look at what application delivery controllers now offer. ADCs now have some cutting-edge …

However, none of the major storage suppliers use erasure coding with their flash products as a protection mechanism against device failure, with the exception of Pure Storage, which uses anN+2erasure coding scheme on its latest FlashBlade platform.

Send me notifications when other members comment.

Obviously, any data protection scheme needs to minimise the impact of device writes on the media. A standard RAID-5 implementation will perform two writes for each host I/O write: one for the data and one for the updated parity. There are also two reads (data and parity), but these dont impact on flash lifetime. RAID-6 implementations require three writes for each host I/O as there are two parity blocks to be updated.

Clustering for high availability and HPC

Enjoy this article as well as all of our content, including E-Guides, news, tips and more.

Q&A: From backup to data management

Performance, monitoring and optimisation

RAID rebuilds also have an impact on performance. All devices in a RAID group are involved in recreating lost data, potentially resulting in degradation of host input/outputinput/output(I/O) performance, or elongated rebuild times.

At its simplest level, RAID-5/6 is similar to erasure coding and we see that being used by VMware inVirtual SANfor data protection across multiple physical vSphere nodes in a cluster.

The benefits of flash with erasure coding are currently lost due to the fact that current erasure coding deployments (with the exception of Virtual SAN) are designed to provide geo-dispersed protection and this adds a level of latency that negates flash performance.

Flash is a great media for random read I/O but has a limited write lifetime. The exact number of writes a flash drive can sustain is based on multiple factors including the type of NAND flash in use and the efficiency of controller algorithms used to manage the media. Drives can have capacities from as little as 0.1 to 10device writes per day(DWPD),and this resiliency is directly reflected in the price of flash products.

We have seen withhard disk drives (HDDs)that an increase in drive capacities and RAID groups results in significant recovery times for failed devices, during which time data can be unprotected against the subsequent failure of another device in the same RAID group. Hence the use of RAID-6 as a protection scheme.

HPE 3PAR recently introduced compression to 3PAR OS 3.3.1 to complement data deduplication, which writes only new data to physical media. Dedupe saves on physical space (making flash costs more attractive), but also reduces the number of physical I/Os that hit media, by filtering out duplicate data as updates are initially written to the array. With highly replicated data (like virtual machines or desktops), savings can be significant.

Erasure coding provides greater efficiency in implementing data protection across datacentres.

Veritas reinvents itself, adding intelligence to data protection

Security information and event management tools give organizations enhanced network management functionality, such as automatic …

Automation Anywhere offers off-the-shelf plug-n-play bots

Doubling or tripling the I/O count for RAID protection isnt an appealing scenario for flash drives, and array suppliers need to implement systems that mitigate this problem.

News roundup: Dragos researchers say the group behind the Trisis malware has expanded its ICS attacks. Plus, Roaming Mantis …

IBM adds deduplication to Spectrum Virtualize, and Storwize arrays

Business intelligence and analytics

How does RAID 5 or RAID 6 affect storage performance …

Erasure coding is mooted asa potential successor to RAID and backup software.

RAID has typically been deployed as a way of recovering failed media within a single storage array or server, although network RAID implementations do exist.

In a similar fashion, NetApp Data Ontap minimises writes in place by always writing new data. Most all-flash suppliers have introduced variations on RAID that are flash friendly.Kaminariohas K-RAID, Hitachi protects data on its FMD modules using standard RAID implementations; IBM uses RAID on FlashSystem.

Data journalism reporters need tools that deliver quick context for stories on deadline. A data collaboration platform from …

Microsoft revives MAID with Pelican, but tape can still sleep easy

Data Breach Incident Management and Recovery

Progress ups front-end & back-end developer tools

Datacentre backup power and power distribution

Flash storage needs array data protection. We run the rule over RAID for flash storage and look at erasure coding, which will become more attractive as drive sizes increase

Hello, GDPR. May 25 is the witching hour for enforcement of the EUs much-discussed GDPR compliance requirements — and its a …

The use of flash with media protection schemes needs some special considerations.

Telecoms networks and broadband communications

Secure Coding and Application Programming

Microsoft revives MAID with Pelican, but tape can still sleep easy

As already mentioned, RAID has issues with scalability, with RAID-5 being particularly vulnerable to unrecoverable read errors. In this scenario, if a rebuild is taking place and one of the remaining data or parity components experiences a drive read error, then the missing data cannot be recovered. RAID-6 mitigates this issue at the expense of more parity and an impact on performance.

RAID vs erasure coding for flash storage

Rob Clyde, chairman-elect of ISACAs board of directors, worries a lot about the world according to qubits. He explains why here …

CIO interview: Chris Ashworth, CIO, Hermes

10 robust USB drive security tools for India Inc

Detection of advanced threats is the top challenge for 55% of security operations centers, according to a new survey, as more …

Mobile device management (MDM) vs backup

This email address doesnt appear to be valid.

You have exceeded the maximum character limit.

By submitting my Email address I confirm that I have read and accepted the Terms of Use andDeclaration of Consent.

But, performing the erasure code transformation on data represents a performance impact to the application, on both read and write. This is because the maths is computationally complex for other than simple protection schemes and because data may have to be read from multiple systems across thewide area network.

Another write reduction technique used by almost all the array suppliers is to implement data reduction technologies such as compression and deduplication.

Siemens Datrium NVMe flash speeds customer software deployment

Security community urged to prepare for quantum computing

Compliance Regulation and Standard Requirements

Scality Zenko multi-cloud controller offers hybrid cloud boost

You forgot to provide an Email Address.

Is it time to move from data protection to information management?

No problem! Submit your e-mail address below. Well send you an email containing your password.

Drive internals (such as the controller orNAND) can fail, and of course drives have a specific lifetime. Onceendurance levelsare reached for a particular cell in NAND, then the media is at risk of failing or returning false results.

At first glance, this coding scheme may seem no more useful than RAID, buterasure codinghas obvious benefits when used as a process of recovering data geographically dispersed across multiple datacentres.

As a result, we continue to requiredata protection methodsagainst media failure, using recovery techniques such asredundant array of inexpensive disks (RAID) and erasure coding.

The main issue when using RAID for data protection is that of scalability. Large RAID groups reduce the overhead of the parity space, but result in increased rebuilds due to failures.

Digitising the BFI National Archive

Scality Zenko multi-cloud controller offers hybrid cloud boost

How Turkish mobile operators are helping the vast Syrian refugee population to help themselves

Backup 101: Incremental vs differential backup

Backup 101: Incremental vs differential backup

The ADC is no hot, new networking tool, but its evolved dramatically, adding some features in its latest iterations that promise…

Dell EMCs XtremIOall-flash array, for example, buffers host I/O until there is sufficient data to write an entire RAID stripe across 23 data and two parity drives. The result is that the write overhead for XDP (XtremIO Data Protection) is 1.2x the number of host writes compared to 3x for standard RAID-6.

Both RAID and erasure coding have benefits and disadvantages that make them suitable for different types of workloads.

What about erasure coding and flash?

Hyper-convergence + backup software = scale-out backup nodes

In our example, imagine distributing four pieces of our 16 pieces of data across four separate datacentre locations. The erasure coding scheme could recover from the loss of any one single datacentre without having to create entire replicas of the original information. In addition, each time data is updated, reading any 10 of the pieces will allow the data to be read, without the need for traditional replication.

RAID is a protection technique that uses data redundancy to protect against device failure.

Leave a Reply