|This article relies largely or entirely upon a single source. (June 2011)|
In computer storage, NetApp filer, known also as NetApp Fabric-Attached Storage (FAS), or NetApp's network attached storage (NAS) device are NetApp's offering in the area of storage systems. A FAS functions in an enterprise-class storage area network (SAN) as well as a networked storage appliance. It can serve storage over a network using file-based protocols such as NFS, CIFS, FTP, TFTP, and HTTP. Filers can also serve data over block-based protocols such as Fibre Channel (FC), Fibre Channel over Ethernet (FCoE) and iSCSI. NetApp Filers implement their physical storage in large disk arrays.
Most other large storage vendors' filers tend to use commodity computers with an operating system such as Microsoft Windows Storage Server or tuned Linux. NetApp filers use highly customized hardware and the proprietary Data ONTAP operating system, both originally designed by founders David Hitz and James Lau specifically for storage-serving purposes. Data ONTAP is NetApp's internal operating system, specially optimised for storage functions at high and low level, it is booted from FreeBSD as a stand-alone kernel-space module and use some functions of FreeBSD (command interpreter and drivers stack, for example).
All filers have battery-backed NVRAM, which allows them to commit writes to stable storage quickly, without waiting on disks. Early filers connected to external disk enclosures via SCSI, while modern models (as of 2009[update]) use FC and SAS protocol. The disk enclosures (shelves) support FC hard disk drives, as well as parallel ATA, serial ATA and Serial attached SCSI.
Implementers often organize two filers in a high-availability cluster with a private high-speed link, either Fibre Channel, InfiniBand, or 10G Ethernet. One can additionally group such clusters together under a single namespace when running in the "cluster mode" of the Data ONTAP 8 operating system.
Most NetApp filers consist of customized computers with Intel or AMD processors using PCI. Each Filer has a proprietary NVRAM adapter to log all writes for performance and to play the data log forward in the event of an unplanned shutdown. One can link two filers together as a cluster, which NetApp (as of 2009) refers to using the less ambiguous term "Active/Active".
Data ONTAP OS
The Data ONTAP operating system implements a single proprietary file-system called WAFL. When used for file storage, Data ONTAP acts as an NFS server and/or a CIFS server, serving files to both Unix-like clients and to Microsoft Windows clients from the same file systems. This makes it possible for Unix and Windows to share files by the use of three security styles: mixed, ntfs, and unix. Data ONTAP supports user, group, and tree-based quotas (referred to as q-trees) and allows for data segregation and management within volumes. Qtrees with the UNIX security style will preserve the standard Unix permission-bits, the NTFS security style will preserve NT ACLs found in the Windows environment, and the mixed security allows the use of both interchangeably (with minor loss of fidelity). Since 2002, all NetApp FAS systems can also work as SAN storage over "block-based" protocols such as FC, iSCSI and FCoE (since 2007).
Each filer model comes with a set configuration of processor, RAM and NVRAM, which users cannot expand after purchase. With the exception of some of the entry point storage controllers, the NetApp filers have at least one PCIe-based slot available for additional network, tape and/or disk connections. In June 2008 NetApp announced the Performance Acceleration Module (or PAM) to optimize the performance of workloads which carry out intensive random reads. This optional card goes into a PCIe slot and provides additional memory (or cache) between the disk and the filer RAM/NVRAM, thus improving performance.
NetApp supports either SATA, Fibre Channel, or SAS disk drives, which it groups into RAID (Redundant Array of Inexpensive Disks or Redundant Array of Independent Disks) groups of up to 28 (26 data disks plus 2 parity disks). Multiple RAID groups form an "aggregate"; and within aggregates Data ONTAP operating system sets up "flexible volumes" to actually store data that users can access. An alternative is "Traditional volumes" where one or more RAID groups form a single static volume. Flexible volumes offer the advantage that many of them can be created on a single aggregate and resized at any time. Smaller volumes can then share all of the spindles available to the underlying aggregate. Traditional volumes and aggregates can only be expanded, never contracted. However, Traditional volumes can (theoretically) handle slightly higher I/O throughput than flexible volumes (with the same number of spindles), as they do not have to go through an additional viritualisation layer to talk to the underlying disk.
WAFL File System
WAFL, as a robust versioning filesystem, provides snapshots, which allow end-users to see earlier versions of files in the file system. Snapshots appear in a hidden directory:
~snapshot for Windows (CIFS) or
.snapshot for Unix (NFS). Up to 255 snapshots can be made of any traditional or flexible volume. Snapshots are read-only, although Data ONTAP 7 provides additional ability to make writable "virtual clones", based at "WAFL snapshots" technique, as "FlexClones".
Data ONTAP implements snapshots by tracking changes to disk-blocks between snapshot operations. It can set up snapshots in seconds because it only needs to take a copy of the root inode in the filesystem. This differs from the snapshots provided by some other storage vendors in which every block of storage has to be copied, which can take many hours.
Snapshots form the basis for NetApp disk replication technology SnapMirror, which effectively replicates snapshots between two NetApp filers. Later versions of Data ONTAP introduced cascading replication, where one volume could replicate to another and then another etc. NetApp also offers a backup product based around replicating and storing snapshots, called SnapVault. Open Systems SnapVault allows Windows and UNIX hosts to back up data to a NetApp filer and store any filesystem changes in snapshots.
Data ONTAP also implements an option called "SyncMirror" where all the RAID groups within an aggregate or traditional volume can be duplicated to another set of hard disks, typically at another site via a Fibre Channel link. NetApp provides a "MetroCluster" option, that uses "SyncMirror" to provide a geo-cluster or active/active cluster between two sites up to 100 km apart.
Other product options include "SnapLock" which implements a "Write Once Read Many" functionality on magnetic disks instead of to optical media, so that data cannot be deleted until its retention period has been reached. SnapLock exists in two modes: compliance and enterprise. The compliance mode was designed to assist organizations in implementing a comprehensive archival solution that meets strict regulatory retention requirements such as dictated by the SEC and several healthcare governing bodies. Records and files committed to WORM storage on a SnapLock Compliance volume cannot be altered or deleted before the expiration of their retention period. Moreover, a SnapLock Compliance volume cannot be destroyed until all data have reached the end of their retention period.
SnapLock Enterprise is geared toward assisting organizations that are more self-regulated and want to have greater flexibility in protecting digital assets with WORM-type data storage. Data stored as WORM on a SnapLock Enterprise volume are protected from alteration or modification with one main difference from SnapLock Compliance: as the files being stored are not for strict regulatory compliance, a SnapLock Enterprise volume can be destroyed by an administrator with root privileges on the FAS system containing the SnapLock Enterprise volume, even if the designed retention period has not yet passed. In both modes, the retention period can be extended, but not shortened, as this is incongruous with the concept of immutability. In addition, NetApp SnapLock data volumes are equipped with a tamper-proof compliance clock that is used as a time reference to block forbidden operations on files, even if the system time is tampered with.
PAM / Flash Cache
NetApp Filer can have PAM ( Performance Accelerate Module ) or Flash Cache (PAM II) which can reduce read latencies and allows the filer to support more read intensive work without adding any further disk to the underlying RAID.
NetApp also offers products for taking application-consistent snapshots by coordinating the application and the NetApp Storage Array. These products support Microsoft Exchange, Microsoft SQL Server, Microsoft Sharepoint, Oracle, SAP and VMware ESX Server data. These products form part of the SnapManager suite.
Prior to the release of ONTAP 8, individual aggregate sizes were limited to a maximum of 2TB for FAS250 models and 16TB for all other models.
The limitation on aggregate size, coupled with increasing density of disk drives, served to limit the performance of the overall system. NetApp, like most storage vendors, increases overall system performance by parallelizing disk writes to many different spindles (disk drives). Large capacity drives, therefore limit the number of spindles that can be added to a single aggregate, and therefore limit the aggregate performance.
Each aggregate also incurs a storage capacity overhead of approximately 7-11%, depending on the disk type. On systems with many aggregates this can result in lost storage capacity.
However, the overhead comes about due to additional block-checksumming on the disk level as well as usual file system overhead, similar to the overhead in file systems like NTFS or EXT3. Block checksumming helps to insure that data errors at the disk drive level do not result in data loss.
Data ONTAP 8.0 supports a new 64bit aggregate format, which increases the size limit to approximately 100TB (depending on storage platform) thus restoring the ability to configure large spindle counts to increase performance and storage efficiency. ()
|Model||Status||Released||CPU||Main memory||NVRAM||Raw capacity||Benchmark||SPECsfs|
|FASServer 400||Discontinued||Jan 1993||50 MHz Intel i486||? MB||4 MB||14 GB||?|
|FASServer 450||Discontinued||Jan 1994||50 MHz Intel i486||? MB||4 MB||14 GB||?|
|FASServer 1300||Discontinued||Jan 1994||50 MHz Intel i486||? MB||4 MB||14 GB||?|
|FASServer 1400||Discontinued||Jan 1994||50 MHz Intel i486||? MB||4 MB||14 GB||?|
|FASServer||Discontinued||Jan 1995||50 MHz Intel i486||256 MB||4 MB||? GB||640|
|F330||Discontinued||Sept 1995||90 MHz Intel Pentium||256 MB||8 MB||117 GB||1310|
|F220||Discontinued||Feb 1996||75 MHz Intel Pentium||256 MB||8 MB||? GB||754|
|F540||Discontinued||June 1996||275 MHz DEC Alpha 21064A||256 MB||8 MB||? GB||2230|
|F210||Discontinued||May 1997||75 MHz Intel Pentium||256 MB||8 MB||? GB||1113|
|F230||Discontinued||May 1997||90 MHz Intel Pentium||256 MB||8 MB||? GB||1610|
|F520||Discontinued||May 1997||275 MHz DEC Alpha 21064A||256 MB||8 MB||? GB||2361|
|F630||Discontinued||June 1997||500 MHz DEC Alpha 21164A||512 MB||32 MB||464 GB||4328|
|F720||Discontinued||Aug 1998||400 MHz DEC Alpha 21164A||256 MB||8 MB||464 GB||2691|
|F740||Discontinued||Aug 1998||400 MHz DEC Alpha 21164A||512 MB||32 MB||928 GB||5095|
|F760||Discontinued||Aug 1998||600 MHz DEC Alpha 21164A||1 GB||32 MB||1.39 TB||7750|
|F85||Discontinued||Feb 2001||256 MB||64 MB||648 GB|
|F87||Discontinued||Dec 2001||1.13 GHz Intel P3||256 MB||64 MB||576 GB|
|F810||Discontinued||Dec 2001||733 MHz Intel P3 Coppermine||512 MB||128 MB||1.5 TB||4967|
|F820||Discontinued||Dec 2000||733 MHz Intel P3 Coppermine||1 GB||128 MB||3 TB||8350|
|F825||Discontinued||Aug 2002||733 MHz Intel P3 Coppermine||1 GB||128 MB||3 TB||8062|
|F840||Discontinued||Aug/Dec? 2000||733 MHz Intel P3 Coppermine||3 GB||128 MB||6 TB||11873|
|F880||Discontinued||July 2001||Dual 733 MHz Intel P3 Coppermine||3 GB||128 MB||9 TB||17531|
|FAS920||Discontinued||May 2004||2.0 GHz Intel P4 Xeon||2 GB||256 MB||7 TB||13460|
|FAS940||Discontinued||Aug 2002||1.8 GHz Intel P4 Xeon||3 GB||256 MB||14 TB||17419|
|FAS960||Discontinued||Aug 2002||Dual 2.2 GHz Intel P4 Xeon||6 GB||256 MB||28 TB||25135|
|FAS980||Discontinued||Jan 2004||Dual 2.8 GHz Intel P4 Xeon MP 2 MB L3||8 GB||512 MB||50 TB||36036|
|FAS250||EOA 11/08||Jan 2004||600 MHz Broadcom BCM1250 dual core MIPS||512 MB||64 MB||4 TB|
|FAS270||EOA 11/08||Jan 2004||650 MHz Broadcom BCM1250 dual core MIPS||1 GB||128 MB||16 TB||13620*|
|FAS2020||EOA||June 2007||2.2 GHz Mobile Celeron||1 GB||128 MB||68 TB|
|FAS2040||Sept 2009||1.66 GHz Intel Xeon||4 GB||512 MB||136 TB|
|FAS2050||June 2007||2.2 GHz Mobile Celeron||2 GB||256 MB||104 TB||20027*|
|FAS2220||June 2012||1.73 GHz Dual Core Intel Xeon C3528||6 GB||768 MB||180 TB|
|FAS2240||November 2011||1.73 GHz Dual Core Intel Xeon C3528||6 GB||768 MB||432 TB||38000|
|FAS3020||EOA 4/09||May 2005||2.8 GHz Intel Xeon||2 GB||512 MB||84 TB||34089*|
|FAS3040||EOA 4/09||Feb 2007||Dual 2.4 GHz AMD Opteron 250||4 GB||512 MB||336 TB||60038*|
|FAS3050||Discontinued||May 2005||Dual 2.8 GHz Intel Xeon||4 GB||512 MB||168 TB||47927*|
|FAS3070||EOA 4/09||Nov 2006||Dual 1.8 GHz AMD dual core Opteron||8 GB||512 MB||504 TB||85615*|
|FAS3140||EOA 2/12||June 2008||Single 2.4 GHz AMD Opteron Dual Core 2216||4 GB||512 MB||420 TB||SFS2008||40109*|
|FAS3160||EOA 2/12||Dual 2.6 GHz AMD Opteron Dual Core 2218||8 GB||2 GB||672 TB||SFS2008||60409*|
|FAS3170||EOA 2/12||June 2008||Dual 2.6 GHz AMD Opteron Dual Core 2218||16 GB||2 GB||840 TB||SFS97_R1||137306*|
|FAS3210||Nov 2010||Single 2.3 GHz Intel Xeon(tm) Processor (E5220)||8 GB||2 GB||480 TB||SFS2008||64292|
|FAS3220||Nov 2012||Single 2.3 GHz Intel Xeon(tm) Quad Processor (L5410)||24 GB||3.2GB||1440 TB||??||??|
|FAS3240||Nov 2010||Quad 2.33 GHz Intel Xeon(tm) Processor (Harpertown)||16 GB||2 GB||1,200 TB||??||??|
|FAS3250||Nov 2012||Dual 2.33GHz Intel Xeon(tm) Processor L5410||40 GB||4 Gb||2,160 TB||SFS2008||100922|
|FAS3270||Nov 2010||Dual 3.0 GHz Intel Xeon(tm) Processor (E5240)||32 GB||4 GB||1,920 TB||SFS2008||101183|
|FAS6030||EOA 6/09||Mar 2006||Dual 2.6 GHz AMD Opteron||32 GB||512 MB||840 TB||SFS97_R1||100295*|
|FAS6040||Dec 2007||2.6 GHz AMD dual core Opteron||16 GB||512 MB||840 TB|
|FAS6070||EOA 6/09||Mar 2006||Quad 2.6 GHz AMD Opteron||64 GB||2 GB||1,008 TB||136048*|
|FAS6080||Dec 2007||4 to 8 2.6 GHz AMD dual core Opteron||64 GB||4 GB||1,176 TB||SFS2008||120011*|
|FAS6210||Nov 2010||2x 2.27 GHz Intel Xeon(tm) Processor E5520||48 GB||8 GB||2,400 TB|
|FAS6220||Feb 2013||2x 64-bit 4-core Intel(R) Xeon(R) Processor E5520||96 GB||8 GB||4,800 TB|
|FAS6240||Nov 2010||2x 2.53 GHz Intel Xeon(tm) Processor E5540||96 GB||8 GB||2,880 TB||SFS2008||190675|
|FAS6250||Feb 2013||2x 64-bit 4-core||144 GB||8 GB||5,760 TB|
|FAS6280||Nov 2010||2x 2.93 GHz Intel Xeon(tm) Processor X5670||192 GB||8 GB||2,880 TB|
|FAS6290||Feb 2013||2x 64-bit 6-core||192 GB||8 GB||5,760 TB|
|Model||Status||Released||CPU||Main memory||NVRAM||Raw capacity||Benchmark||SPECsfs|
EOA = End of Availability
SPECsfs with "*" is clustered result. SPECsfs performed include SPECsfs93, SPECsfs97, SPECsfs97_R1 and SPECsfs2008. Results of different benchmark versions are not comparable.
- Nabrzyski, Jarek; Schopf, Jennifer M.; Węglarz, Jan (2004). Grid Resource Management: State of the Art and Future Trends. Springer. p. 342. ISBN 978-1-4020-7575-9. Retrieved 11 June 2012.