Eye-POPing results in NAS server tests

Posted on January 01, 2004

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FIA's Gigabit NAS server turns in impressive throughput results, but performance depends on the operating environment.

By Jack Fegreus

With the explosion of rack-mounted servers and the emergence of server blades in self-contained clusters, an old problem re-emerges: how to deal with storage. With many new systems having no room for internal storage beyond the bare minimum to boot and get up and running, the focus once again spins toward networked storage. From 2Gbps Fibre Channel storage area networks (SANs) to iSCSI and the stalwart network-attached storage (NAS), attention has turned to how to quickly attach and easily maintain storage devices on a network, while simultaneously satisfying the insatiable appetite for more capacity.


Figure 1: Interestingly, the end-user application FIAPOP Data Replicator was able to discover the POPnetservers on both Windows and Linux; however, the authorization function only worked while running on a real Windows distribution.
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One of the least expensive solutions by far has been a traditional NAS server built on RAID arrays based on Parallel ATA rather than SCSI drives. Performance on such RAID systems is often good enough to satisfy the needs of a direct-connect storage subsystem, as well as networked storage.

This is the architectural model followed by First Intelligent Array (FIA) in its POPnetserver line of NAS devices, which use hot-swap Ultra ATA disk drives and FreeBSD software. The FIA POPnetserver 4600 model 720 tested by openBench Labs features a 2GHz P4 processor, two Intel 10/100/1000 Gigabit Ethernet ports and a third Intel 10/100 Fast Ethernet port, and four hot-swap 180GB Parallel Ultra ATA drives. When the four drives were configured as a single RAID 5 volume, the POPnetserver provided us with instantaneous access to over 500GB of storage at a cost of just over $3,000.

Configuration and management of the POPnetserver is extremely simple. However, all of the management software is designed to run on Windows—and only Windows (the management console system must be running Windows 95, 98, Me, NT 4.0, 2000, or XP, and Microsoft Internet Explorer version 5.0 or later for a Web browser).


Figure 2: POPmanage, which provides the functionality to configure and control the POPnetserver, uses a Java applet that must be run on Windows or a Linux system running CrossOver Office. Logging into the server will work from any browser. Nonetheless, the POPmanage applet will only appear in a Windows support environment.
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FIA takes the notion of providing customers with a true "appliance" very seriously. The idea is to provide users with little—or no—IT proficiency with the wherewithal to install and set up a POPnetserver. This goes all the way to supplying color-coded Category 5e Ethernet cables, including a crossover cable for sites with no Ethernet hub.

Accompanying the POPnetserver is a CD with POPassist, a software application designed to help administrators manage the NAS appliance. In addition, there is FIAPOP Data Replicator, which provides a point-and-click mechanism for Windows users to utilize the POPnetserver as an online backup-and-restore appliance.

The first thing that POPassist does is discover all of the POPnetservers on the network. Making this discovery process all the more tricky, FIA ships each NAS server with an initial configuration that names the POPnetserver "POP4600XXXXX," where XXXXX is the unit's serial number. So if an administrator looks in the My Network Neighborhood, or My Network Places, or even the LiSA LAN Browser on a Linux system, any device that begins with "POPnetserver" will more than likely be the server in question.

Having automated the discovery process, the first function an administrator will want to do is configure the underlying drives and folders that will be shared from a server. Once POPassist identifies the NAS server, clicking on the POPmanage button launches MS Internet Explorer to the server's IP address to start the process. Note that getting to the server and its Web-based utility could easily be done manually with any browser. Nonetheless, this is where things get interesting.

Prior to taking that step, we were able to run—albeit not completely—POPassist on SuSE Linux Desktop with the help of CrossOver Office. The only glitch comes in actually finding the POPnetserver. That function would not work, which left us manually inputting the new address we discovered with LiSA and My Network Places.

Levity aside, there is a crucially important function that a system administrator will need POPassist in order to perform: POPbackup. Using POPbackup, an administrator can back up or restore any combination of vital POPnetserver configuration data and/or user data stored on the POPnetserver to another storage device on the network. Naturally, this function works perfectly with Windows running on the client. In addition, by using CrossOver Office, we were also able to run POPbackup on a laptop running SuSE Linux Desktop.


Figure 3: The real test of the POPnetserver's mettle came when we mounted shares on our HP ML350 G3 Server. With its dual Xeon processors, the server devoured data from the NAS appliance. Interestingly, performance in our tests was strongly dependent on the operating system being used on the server acting as a POPnetserver client. We used the oblDisk v1.0 benchmark for performance tests.
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Unfortunately, this cross platform compatibility did not extend to the end-user application FIAPOP Data Replicator. This is a very slick and easy-to-use application that makes end-user backup a reasonable proposition. Like its sibling POPassist, FIAPOP begins by discovering POPnetservers on the LAN and simplifies connection for users.

Once authorized on the POPnetserver, a first-time user can then identify any folders on the desktop system to be replicated on the server. Once that is done, the replication process is as simple as clicking on the Upload button. The FIA takes this one-step function further by allowing the user to designate which folders are to be monitored for changes. Once this is done, the next time the user wants to back up important data, there will be a choice to either replicate all data, or back up only the data that has changed in the monitored folders. This can save significant time as only those files on the user's computer that have been changed since the last update will now be uploaded to the POPnetserver.

For Windows users, this process runs very smoothly. However, the efficiency breaks down for users running Linux. Since FIAPOP is an end-user tool, it begins by attempting to get authorization on the requested POPnetserver for the current end user. This function fails with CrossOver Office, which immediately ends the process.

Managing the POPnetserver from the POPmanage Web interface is equally simple, once you get there. The POPnetserver runs on the FreeBSD operating system and can be accessed using any Web browser on any system. The process starts with the pre-sentation of a login form. Once an administrator submits the form and is authorized on the server, a Java applet pops up on the central portion of the screen. The Java applet enables the actual management of the Free-BSD server and, like so many other such applets, has been debugged only on Windows systems—or a Linux system with CrossOver Office.

On any other system, the central management foreground screen disappears and the administrator is confronted by just the blue FIA backdrop. It sort of breathes life into the old saying about Java: Write once, debug everywhere.

With the Java applet functioning, administrators and authorized users have a wealth of information at their fingertips. The POPnetserver status page graphically lays out the current operation status of the server. This includes the frequency of ECC errors, temperature, network ports, fans, power supplies, and hard-disk usage. If an error such as a memory error, high temperature, network card malfunction, fan malfunction, power supply malfunction, or hard-disk failure occurs on the server, the information on this page is immediately updated. In addition, the server can also be configured so that whenever a significant event occurs, the system will automatically send an e-mail notification message to the administrator.

The POPnetserver 4600 offers a simple and easy-to-use approach to change and modify system and network parameters, set up Windows, Unix, Novell, and Apple Macintosh network settings, and configure and maintain the internal hard disks. The system administrator can segment the POPnetserver storage space into multiple shared volumes. The administrator has control over user access rights of these shared folders through a central form with tabs for setting unique properties and privileges for Windows, NFS, Apple, and Novell shares. The administrator can also set up a volume snapshot policy, which can be configured down to an hourly level. When snapshots are taken, issues such as how long snapshots are retained and who has access to the files are all determined by the administrator.

In addition, unlike sharing files from a system running Windows 2003 Server, every user can be granted access to the time-based snapshots. From a Windows 2003 Server, snapshots can only be accessed by Windows clients, only if those clients upgrade their Network Neighborhood applet from the server.

For sites expecting to have a high amount of traffic, administrators can configure multiple LAN ports as a "team." In such a configuration, also dubbed "trunking" or "link aggregation," the POPnetserver simulates a large-scale LAN port by sharing the same network address across all of the individual network interface cards (NICs) and consolidating their overall network bandwidth. In addition, if any NIC fails the others simply continue to run, so a significant degree of network resiliency and redundancy is added.

There are, however, three noteworthy caveats to the NIC teaming scheme: Each NIC in the team must have the same bandwidth. A 100Mbps NIC cannot be teamed with a 1,000Mbps NIC. Second, "trunking" is only available when coupled with a switch that supports Cisco Fast EtherChannel (FEC). Third, trunking is really a network switching function, so its value only arises when there are multiple simultaneous users.

To test the performance capabilities of the POPnetserver 4600, we attached to the server from both an HP Compaq EVO laptop client with an Intel 100Mbps Fast Ethernet LAN card built-in and an HP ML350 G2 server with dual Intel Xeon processors and dual Gigabit Ethernet NICs. As expected, using Samba and NFS from the client laptop provided little insight into performance. From Windows XP Pro or SuSE Linux Desktop, whether using volumes shared over NFS or Samba, performance was basically at wire speed. We could consistently read data from the share on the order of 9MBps to11MBps and write data on the order of 8MBps.

When we moved to the server, however, things got interesting. In the first tests, we ran SuSE Linux Enterprise Server (SLES) on the ML350 G2 system. We configured fstab to import and mount an SMBFS—Windows share—volume from our POPnetserver. Using single-threaded reads and writes, performance was an expected ho-hum. As we had measured with earlier systems, Gigabit jumbo packets or no jumbo packets, throughput at about 13MBps on reads was less than blinding. What's more, it did not get better with more processes.

However, that all changed when we tested another share imported via NFS. This time we obtained throughput results worthy of the server. Single-threaded reads were in the neighborhood of 17MBps to 18MBps. Also, throughput on reads moved up into the range of 75MBps to 83MBps with four threads.

On the other hand, writes remained right were they were with 100Mbps Fast Ethernet. Since we couldn't stress the bandwidth of 100Mbps Ethernet performing writes, there was no reason to expect conditions to change with Gigabit Ethernet.

We then ran Windows 2003 Server Enterprise Edition on the ML 350 system to test the Samba shares from a true Windows system. The results showed a dramatic improvement in performance. Mounting the Samba shares from the POPnetserver under Windows 2003 Server, throughput scaled in a similar fashion to what we had measured under NFS on SLES.

Jack Fegreus is the research director at Strategic Communications (www.strat comm-inc.com). He can be contacted at jfegreus@stratcomm-inc.com.


Lab scenario

Under examination
Free BSD-based NAS server with Windows, Unix, Apple, and Novell networking support

What we tested

  • FIA POPnetserver 4600 Model 720
  • Free BSD
  • 1U form factor
  • 2GHz P4 CPU
  • (4) Hot-swap Ultra ATA disk drives
  • (2) Intel 10/100/1000-Mbps Ethernet ports
  • RAID 0, 1, 5

How we tested

HP Compaq EVO laptop

  • Windows XP Professional
  • SuSE Linux Desktop v1
    —CrossOver Office 2.0.1
  • Mandrake Linux 9.2

HP ML350 G2 Server

  • Dual 2.4GHz Intel Xeon CPUs
  • Dual Gigabit Ethernet ports
  • Windows 2003 Server EE
    —.NET Framework 1.1
  • SuSE Linux Enterprise Server v8
    —Linux kernel 2.4.19
    —Multi-path I/O

Benchmark

oblDisk 1.0

Key findings

  • System is designed as a true appliance.
  • Configuration software is explicitly designed to work with Windows; however, most functions will run on Linux supplemented with CrossOver Office.
  • Best Gigabit Ethernet performance measured with Windows accessing volumes shared with Samba and Linux accessing volumes shared using NFS. For laptop clients on Fast Ethernet, both Samba and NFS shares were wire-speed limited.


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