What you’ll learn in this tip: When it comes to storage opening management, there’s no tip recipe for present success.
But there are intelligent ways to proceed a problem. Read these 10 tips to find out how things like
continuous information insurance (CDP), active multipathing and infrequently simply doubt a number
of queries users contention can make a disproportion in your shop.
Given a choice between fine-tuning information storage for ability or for performance, many data
storage managers would select a latter. Tips and tricks to boost storage speed are common, but
they’re not all equally effective in any environment. A accumulation of products and technologies do
have good intensity for many shops, from optimizing server-side entrance to improving the
storage-area network (SAN). We’ll demeanour during some effective, nonetheless mostly overlooked, methods to speed up
storage complement performance.
Networked storage is impossibly complex, requiring a diverse
set of hardware and software
elements to interoperate smoothly. Not surprisingly, one of a many common causes of delayed storage performance is a misconfiguration or tangible disaster of one or more
of these components. Therefore, a initial place to demeanour for softened opening is in a existing
storage I/O stack.
Check server and storage array logs for signs of earthy faults; I/O retries, trail transformation and
timeouts along a organic couple are certain signs. Try to besiege a unwell element, nonetheless start with
cable-related components. Flaky transceivers and cables are common, and can severely impact
performance while still vouchsafing things run good adequate to go unnoticed. These apparatus mostly fail
after being physically disturbed, so be generally observant after installation, emigration or
removal of information core equipment.
1. Freshen firmware and drivers
Manufacturers are constantly regulating bugs, and new capabilities can hide in with software
updates. It’s scold to stay on tip of driver and firmware
updates for all components in a storage network, with scheduled and active testing, tuning and
upgrading. Microsoft Corp. and VMware Inc. have been actively adding new opening facilities to
the storage stacks in Windows and vSphere, mostly nonetheless many fanfare. SMB 2.0 and 2.1, for
example, dramatically accelerated Windows record sharing, generally over slower networks. Updates to
NTFS and VMFS have also
routinely softened opening and scalability. Stay tuned to storage blogs and publications to
keep on tip of these developments.
But we should note that not all updates are value a time and effort, and some can be
downright perilous. Make certain your pattern is upheld by all vendors concerned and has been
thoroughly tested, and never use beta formula in production. As a systems administrator, we tend to be
conservative about what we hurl out, watchful for reports from others before holding a plunge
2. Question a queries
Most of a tips concentration on locating and expelling bottlenecks in a storage stack, nonetheless one should also cruise shortening the
I/O bucket before it’s created. Working with database administrators (DBAs) to balance their queries for
efficiency and opening can compensate off vast time, given a reduced I/O effort advantages everybody and
3. Break down backup bottlenecks
Traditional backup applications are intensely fatiguing on storage resources, transfer massive
volumes of information according to a daily and weekly schedule. Improving a performance of backups so they can fit within their reserved “window” has
become a priority for information insurance pros, nonetheless a techniques employed can assistance urge altogether data storage performance as well.
One effective routine to revoke a backup break is to widespread it out regulating continuous information insurance (CDP) technology. Built into many products intended
for practical servers, CDP ceaselessly copies information from a server rather than collecting it in a
single, strong operation. This is generally profitable in virtual appurtenance (VM) environments given a nightly backup “kick off” across
multiple guest can vanquish storage responsiveness, from a train to a horde train adapter (HBA) or
network interface label (NIC) to a array. Microsoft and VMware also have technologies to offload
backup-related snapshots to storage arrays that are softened means to hoop information movement.
4. Offload practical appurtenance I/O with VAAI
The recover of VMware vSphere 4.1 enclosed many new features, nonetheless one of a many vicious was
the vStorage API for Array Integration (VAAI). This new interface allows VMware ESX to coordinate certain I/O tasks with upheld Fibre Channel (FC)
or iSCSI storage systems, integrating a hypervisor and array to work some-more closely and effectively
VAAI includes 3 “primitives,” or formation points:
- Unused storage can be expelled for thin provisioning regulating a fit “write_same” SCSI command, increasing
capacity function and shortening I/O overhead.
- Snapshot and mirroring operations can be offloaded to a storage array,
greatly shortening a network, hypervisor and handling complement I/O workload.
- Access locking can take place during a turn some-more granular than a whole LUN, shortening contention
and wait time for practical machines.
Although nothing of these screams “storage opening tuning,” a net outcome can be a dramatic
reduction in a I/O effort of a hypervisor as good as reduction trade over a SAN. Analysts
expect serve improvements (including NFS support) in destiny versions of VMware vSphere, and one
imagines that Microsoft is operative on identical formation facilities for Hyper-V.
5. Balance practical appurtenance I/O with SIOC
While not a opening acceleration record per se, VMware vSphere Storage I/O Control (SIOC) is a “quality of service” mechanism
that creates I/O performance some-more predictable. SIOC monitors a response latency of VMFS
datastores and acts to stifle behind a I/O of lower-priority machines to say a performance
of others. In practice, SIOC reduces a impact of “noisy neighbors” on prolongation virtual
machines, improving their responsiveness. This helps keep concentration developers and managers
happy, bringing a coming of softened opening even nonetheless sum throughput stays the
What doesn’t work
Besides looking during how to ratchet adult storage network performance, we also need to cruise some
not-so-effective approaches to improving performance. Testing can exhibit engaging outcomes:
Enabling jumbo frames on Ethernet networks, for example, typically hasn’t yielded many of a
One common doubt relates to a merits of several storage protocols and a common belief
that Fibre Channel is inherently faster than iSCSI, NFS or SMB. This isn’t a box generally,
although implementations and configurations vary. Similar architectures furnish identical levels of
performance regardless of protocol.
One should also be discreet about contracting “bare-metal” technologies in practical environments,
including paravirtualized drivers, proceed I/O like VMDirectPath and tender device mapping (RDM). None
delivers many opening alleviation and all meddle with fascinating facilities like VMotion.
6. Streamline a server side
Today’s multicore servers have CPU energy to spare, nonetheless network interface cards (NICs) and HBAs have traditionally been sealed to a
single processor core. Receive-side scaling (RSS) allows these interface cards to distribute
processing opposite mixed cores, accelerating performance.
Hypervisors face another charge when it comes to classification I/O and directing it to
the scold practical appurtenance guest, and this is where Intel Corp.’s practical appurtenance device queues
(VMDq) record stairs in. VMDq allows a Ethernet adapter to promulgate with hypervisors like
Microsoft Hyper-V and VMware ESX, organisation packets according to a guest practical appurtenance they’re
Technologies like RSS and VMDq assistance accelerate I/O trade in perfectionist server virtualization applications, delivering extraordinary levels of performance.
By leveraging these technologies, Microsoft and VMware have demonstrated a correspondence of
placing perfectionist prolongation workloads on practical machines.
7. Get active multipathing
Setting adult mixed paths between servers and storage systems is a normal proceed for high
availability, nonetheless modernized active implementations can urge storage opening as well.
Basic multipathing program merely provides for failover, bringing adult an alternative
path in a eventuality of a detriment of connectivity. So-called “dual-active” configurations assign
different workloads to any link, improving function nonetheless restricting any tie to a single
path. Some storage arrays support trunking mixed connectors together or a full active-active
configuration, where links are many-sided and a full intensity can be realized.
Modern multipathing frameworks like Microsoft MPIO, Symantec Dynamic Multi Path (DMP) and VMware
PSA use storage array-specific plug-ins to capacitate this arrange of active multipathing. Ask your
storage businessman if a plug-in is available, nonetheless don’t be astounded if it costs additional or requires a
special craving license.
8. Deploy 8 Gbps Fibre Channel
Fibre Channel throughput has ceaselessly doubled given a initial 1 Gbps FC products appeared,
yet retrograde harmony and interoperability have been confirmed along a way. Upgrading to
8 Gbps FC is a elementary approach to accelerate storage I/O, and can be remarkably
affordable: today, 8 Gbps FC switches and HBAs are widely accessible and labelled approximately the
same as common 4 Gbps parts. As SANs are stretched and new servers and storage arrays are purchased,
buying 8 Gbps FC rigging instead of 4 Gbps is a no-brainer; and 16 Gbps FC apparatus is on the
Remember that throughput (usually voiced as megabytes per second) isn’t a usually metric of
data storage performance; latency is usually as critical. Often gifted in terms of I/O operations
per second (IOPS) or response time (measured in milliseconds or nanoseconds), latency is a speed
at that particular I/O requests are processed and has turn vicious in virtualized server
environments. Stacking mixed practical servers together behind a singular I/O interface requires
quick estimate of packets, not usually a ability to tide vast amounts of consecutive data.
Each doubling of Fibre Channel throughput also halves a volume of time it takes to routine an
I/O operation. Therefore, 8 Gbps FC isn’t usually twice as discerning in terms of megabytes per second, it
can also hoop twice as many I/O requests as 4 Gbps, that is a genuine bonus for server
9. Employ 10 Gbps Ethernet
Fibre Channel isn’t alone in cranking adult a speed. Ethernet opening has recently jumped by
a cause of 10, with 10 Gbps Ethernet (10 GbE) apropos increasingly common and affordable, nonetheless 10
GbE storage array accessibility lags rather behind NICs and switches. Environments regulating iSCSI or
NAS protocols like SMB and NFS can knowledge large opening improvements by relocating to 10 Gbps
Ethernet, supposing such a network can be deployed.
An choice to end-to-end 10 Gb Ethernet is trunking or fastening 1 Gbps Ethernet links using
the couple assembly control custom (LACP). In this way, one can emanate multigigabyte Ethernet
connections to a host, between switches or to arrays that haven’t nonetheless been upgraded to 10 GbE.
This helps residence a “Goldilocks problem” where Gigabit Ethernet is too delayed nonetheless 10 Gbps Ethernet
isn’t nonetheless attainable.
Fibre Channel over Ethernet (FCoE) brings together a Fibre Channel and
Ethernet worlds and promises softened opening and larger flexibility. Although one would assume
that a 10 Gbps Ethernet links used by FCoE would be 20% faster than 8 Gbps FC, a disproportion in
throughput is an considerable 50%, interjection to a some-more fit encoding method. FCoE also promises
reduced I/O latency, nonetheless this is mitigated when a overpass is used to a normal Fibre Channel
SAN or storage array. In a prolonged term, FCoE will urge performance, and some environments are
ready for it today.
10. Add cache
Although a quickest I/O ask is one that’s never issued, as a means of speeding things up,
caching is a
close second. Caches are appearing via a I/O chain, earnest softened responsiveness by
storing frequently requested information for after use. This is frequency a new technique, but
interest has strong with a appearance of affordable NAND flash
There are radically 3 forms of cache offering today:
- Host-side caches place NVRAM or NAND peep in a server, mostly on a high-performance PCI Express card. These keep I/O off a network nonetheless are usually useful on a
- Caching appliances lay in a network, shortening a bucket on a storage array. These serve
multiple hosts nonetheless deliver concerns about accessibility and information coherence in a eventuality of an
- Storage array-based caches and tiered storage solutions are also common, including NetApp’s
Flash Cache cards (formerly called Performance Acceleration Module or PAM), EMC’s Fully Automated
Storage Tiering (FAST) and Hitachi Data Systems’ Dynamic Tiering (DT).
Still no china bullet
There are many options for improving storage performance, nonetheless there’s still no singular silver
bullet. Although storage vendors are discerning to explain that their latest innovations (from tiered storage to FCoE) will solve information storage opening issues, nothing is
foolish adequate to concentration on usually one area. The many effective opening alleviation strategy
starts with an research of a bottlenecks found in existent systems and ends with a devise to
BIO: Stephen Foskett is an eccentric consultant and author specializing in enterprise
storage and cloud computing. He is obliged for Gestalt IT, a village of eccentric IT
thought leaders, and organizes their Tech Field Day events. He can be found online at
GestaltIT.com, FoskettS.net and on Twitter during @SFoskett.
This essay was creatively published in Storage magazine.
This was initial published in Aug 2011
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