Now NetApp performs server-side caching too

In addition to existing caching technologies, such as Flex Cache and Flex Pool, August 21^st, 2012 NetApp announced the Flash Accel solution which speeds application performance using server-side cache for storing frequently accessed data working with NetApp storage arrays.

The Flash Accel is the software leveraging the existing SSD and PCIe flash memory hardware installed into the servers. Will be supported the SSD and PCI-e flash memory products of Server Partner Caching Alliance members: Fusion-io, LSI, Micron, QLogic, SanDisk (FlashSoft), STEC and Virident.  Also the first version of Flash Accel will support Microsoft Windows Server 2003 and 2008 and VMware vSphere  5. (including DRS, HA and vMotion support).

The Flash Accel provides the following features:

• End-to-End Intelligent Data Coherency: if data blocks are changed on the backend array the Flash Accel will update the local cache accordingly. 
• Cache Persistency and Durability: Flash Accel preserves cache content consistently with applications in the event of server and VM reboot and crashes. After the server restart the cache content is checked and updated as the server is back on, what allows to have a warm cache after restart.

It’s also interesting that competing with other server-side caching solutions such as HP flash cache in Gen8 servers and EMC VFcache the Flash Accel is looking more open allowing to use hardware from different SSD and PCI-e flash memory vendors. 

But anyway, we shouldn’t also forget about other server-side caching solutions which are external storage system independent, e.g. FlashSoft from SANDisk , Nytro XD from LSI or ioTurbine from Fusion IO. 

NetApp and Windows 2008 R2 NFS Connectivity

Just now tried to mount NetApp FAS (IBM N Series) storage resources to the Microsoft Windows 2008 R2 Server, using only NFS license on the filer.

Mounting NFS resource using Microsoft NFS client without user mapping services I got network disk mounted with nobody privileges and could do nothing with it. Of course mapping needs to be set and this process is described in the following post.

  

First of all I thought about filer’s /etc/usermap.cfg where is possible to map Windows users to the correct UNIX accounts to provide UNIX security style for NFS resources. But as far as I understand now, to use this mapping method filer must be integrated into Active Directory and it is possible only when CIFS license is activated.

OK, let’s try to use mapping service for Windows. Oops! When we go to the File Server role we can see that in Windows Server 2008 R2:

User Name Mapping has changed—server functionality no longer exists, but client functionality is present. Services for NFS can still retrieve mappings from existing legacy User Name Mapping servers.

And moreover, User Name Mapping server can’t be installed on Windows 2008 R2 Server – you need to use existing legacy server.

There’s another capability to connect Windows 2008 R2 Server by NFS to NetApp storage resources – try to use the Direct NFS from Oracle, but it can be used only for Oracle needs and I’m not 100% sure about its compatibility with Windows 2008 R2Server.

What I can say, in spite of the fact that NFS works perfectly for UNIX and VMware environment, don’t think, that purchasing only NFS license you can also cover your Windows 2008 R2 Server’s storage requirements, CIFS is also needed.

Some words about NetApp FAS (IBM N series) initial storage configuration

In many cases just delivered NetApp FAS (or IBM N series) storage system isn’t configured as you want, especially if it has two controllers (filers). And if network and storage protection settings can be modified relatively easy, storage reconfiguration needs often much more time, and sometimes system configuration must be rebuild from the scratch.

There are some steps which can save time performing initial storage configuration:

·         Usually, just shipped storage system has the following configuration:

o   aggr0 is built from 3 HDDs, and root volume vol0 is configured for each filer.

o   Other unused HDDs can be assigned to different filers or can remain unassigned.

·         If it’s necessary to redistribute disks across different filers and/or disk shelves:

o   Make a serial connection to both filers: 9600-8-1-None-None

o   For each filer go to the maintenance mode:

§  Perform reboot of each filer: reboot

§  During Data ONTAP boot press Ctrl-C and in boot menu press 5.

o   In maintenance mode see what disks are assigned to what filer type : disk show

o   To see unassigned disks type: disk show -n

o   It’s impossible to reassign already assigned disks. First of all they need to be unassigned. On each filer type: disk assign disk names -s unowned.  Disk names – IDs of disks, which should be given to other filer.

o   Optional, if disks are going to be moved to another disk shelf: stop both filers: halt. Switch power down (filers, then disk shelves), move unassigned disks to required bays. Switch filers on (disk shelves, then filers), boot Data ONTAP in maintenance mode.

o   Assign unassigned disks to the filer by typing on this filer: disk assign disk names. Check that all disks are assigned using disk show and disk show -n commands.

o   Reboot filers in normal mode. During reboot after maintenance mode system periodically stops on the boot loader stage. In this case type boot_ontap and filer will be booted in normal mode.

·             If you add disks to the aggregates using na_admin web console, new raid groups can be created and disk resources may not be optimally used. It’s better to define the maximum size of raid group – maximum quantity of disks per raid group:  aggr aggrname options raidsize number, and after that add required quantity of disks: aggr add aggrname -g raidgroup -d disk names.

Detailed description of commands can be found in DataONTAP Command Guide. It can be found in your filer (http://Filer_IP_address/na_admin/man/index.html)  and NetApp Community public forum.

Data availability tiers - recommendations for NetApp and IBM N series storage

The NetApp features description and usage recommendations for different data availability tiers.

Mission-Critical – high demand services, e.g. OLTP, batch transaction processing, virtualization/cloud environments.

Flash Cache	Use Flash Cache to improve system performance and minimize the impact to foreground I/O while in degraded mode situations.
SyncMirror	Use local SyncMirror to make sure of shelf-level resiliency and to improve performance in degraded mode situations.
Spares	Use a maximum hot spares approach to make sure sufficient disks are available for corrective actions. Set the RAID option raid.min_spares_count to the recommended number of spares to make sure the administrator will be notified when spare counts are reduced below recommendations.
Drive Type	Use performance drives (SAS, FC, or SSD) instead of capacity drives (SATA). Smaller-capacity 15k rpm or SSD drives result in shorter times for corrective actions. This is important when foreground I/O is prioritized over corrective I/O, which increases times for corrective actions. Performance drives help offset that performance delta.
Aggregate Fullness	Monitor aggregate “fullness” as performance degrades as disks get full (the drive heads need to travel farther to complete I/Os). Drive failures further degrade foreground I/O performance when drives are nearing full data capacity.
Utilization Monitoring	Monitor CPU utilization, disk utilization, and loop/stack bandwidth. If your utilization is greater than 50%, you are at increased risk to see greater foreground I/O degradation in degraded mode situations. This can also increase the time it takes for corrective actions to complete.
I/O Prioritization	Prioritize foreground I/O over corrective I/O by adjusting the RAID option raid.reconstruct.perf_impact to Low.
Scrubs	Use the default settings for RAID scrubs and media scrubs. Systems are assumed to be highly utilized, so increasing the duration of scrubs will likely provide a reduced benefit to data integrity while consuming additional system resources.
Maintenance Center	Maintenance Center is recommended to enable intelligent triage of suspect drives in the field. This also facilitates the RMA process for failed drives to make sure the system returns to a normal operating state in a timely manner.

Business-Critical – to meet compliance requirements and/or intellectual property e.g. medical records, software source code, and e-mail.  

Flash Cache	Use Flash Cache to improve system performance and minimize the impact on foreground I/O while in degraded mode situations.
SyncMirror	Use local SyncMirror to make sure of shelf-level resiliency and to improve performance in degraded mode situations.
Spares	Use a maximum hot spares approach to make sure sufficient disks are available for corrective actions. Set the RAID option raid.min_spares_count to the recommended number of spares to make sure the administrator will be notified when spare counts are below recommendations.
Drive Type	Use performance drives (SAS, FC, or SSD) instead of capacity drives (SATA). Smaller-capacity 15k rpm or SSD drives result in shorter times for corrective actions. This is important when foreground I/O is prioritized over corrective I/O, which increases times for corrective actions. Performance drives help offset that performance delta.
Aggregate Fullness	Monitor aggregate “fullness” as performance degrades as disks get full (the drive heads need to travel farther to complete I/Os). Drive failures will further degrade foreground I/O performance when drives near full data capacity.
Utilization Monitoring	Monitor CPU utilization, disk utilization, and loop/stack bandwidth. If your utilization is greater than 50%, you are at increased risk to see greater foreground I/O degradation in degraded mode situations. This can also increase the time it takes for corrective actions to complete.
I/O Prioritization	Use the default setting of Medium for the RAID option raid.reconstruct.perf_impact to balance foreground I/O and corrective I/O.
Scrubs	Consider increasing the frequency of RAID scrubs to increase integrity of data at rest.
Maintenance Center	Maintenance Center is recommended to enable intelligent triage of suspect drives in the field. This also facilitates the RMA process for failed drives so that systems return to a normal operating state in a timely manner.

Repository – used to store collaborative data or user data that is noncritical to business operations .

Flash Cache	Use Flash Cache to improve system performance and minimize the impact on foreground I/O while in degraded mode situations.
SyncMirror	Use local SyncMirror to make sure of shelf-level resiliency and to improve performance in degraded mode situations.
Spares	Use a balanced hot spares approach to allow more disks to be used to add to the system capacity. Set the RAID option raid.min_spares_count to the recommended number of spares so that the administrator will be notified when spare counts are below recommendations.
Drive Type	Consider using SATA drives (backed by Flash Cache) for these types of configurations.
Aggregate Fullness	Monitor aggregate “fullness” as performance degrades as disks get full (the drive heads need to travel farther to complete I/Os). Drive failures will further degrade foreground I/O performance when drives near full data capacity.
Utilization Monitoring	Monitor CPU utilization, disk utilization, and loop/stack bandwidth. If your utilization is greater than 50%, you are at increased risk for greater foreground I/O degradation in degraded mode situations. This can also increase the time it takes for corrective actions to complete.
I/O Prioritization	Use the default setting of Medium for the RAID option raid.reconstruct.perf_impact to balance foreground I/O and corrective I/O.
Scrubs	Consider increasing the frequency of RAID scrubs to increase the integrity of data at rest.
Maintenance Center	Maintenance Center is recommended to enable intelligent triage of suspect drives in the field. This also facilitates the RMA process for failed drives so that systems return to a normal operating state in a timely manner.

Archival – a large initial ingest of data (write), which then is seldom accessed. Priority is maintaining data integrity.

Spares	Use a maximum hot spares approach so that sufficient disks are available for corrective actions. Set the RAID option raid.min_spares_count to the recommended number of spares so that the administrator is notified when spare counts are below recommendations.
Drive Type	Consider using SATA drives (backed by Flash Cache) for these types of configurations.
Aggregate Fullness	Monitor aggregate “fullness” as performance degrades as disks get full (the drive heads need to travel farther to complete I/Os). Drive failures will further degrade foreground I/O performance when drives near full data capacity.
Utilization Monitoring	Monitor CPU utilization, disk utilization, and loop/stack bandwidth. If your utilization is greater than 50%, you are at increased risk for greater foreground I/O degradation in degraded mode situations. This can also increase the time it takes for corrective actions to complete.
I/O Prioritization	Use the default setting of Medium for the RAID option raid.reconstruct.perf_impact to balance foreground I/O and corrective I/O.
Scrubs	Consider increasing the RAID scrub duration (raid.scrub.duration) to help make sure of the integrity of data at rest. Consider increasing the media scrub rate (raid.media_scrub.rate) to increase drive-level block integrity.
Maintenance Center	Maintenance Center is recommended to enable intelligent triage of suspect drives in the field. This also facilitates the RMA process for failed drives so that systems return to a normal operating state in a timely manner.

Multipurpose – mixed environment.

Prioritize Recommendations	Prioritize configuration recommendations for the most sensitive tier of data availability when conflicting recommendations are present.
FlexShare®	Consider using FlexShare to prioritize system resources between data volumes.
Physical Segregation	Segregate the physical shelf and the drive layout for multiple data-availability tiers. For example, if you have both SAS and SATA (DS4243) attached to the same system, you could use the SAS drives to host mission-critical data while using the SATA drives to host archival data. Although you can mix DS4243 SAS shelves with DS4243 SATA shelves in the same stack, NetApp recommends separating the shelves into stacks so that physical failures affecting one tier of data availability will not directly affect both tiers of storage being hosted (in this example).

The full Technical Report from NetApp "Storage Best Practices and Resiliency Guide" can be found here