Getting the Max Out of Attached Storage

• 08/16/2000

The advent of network-attached storage (NAS) presented some relief from adding servers or expensive disk arrays, which can cost well over $10,000. Most storage expansion -- from a security standpoint -- is generally shared to the users without specific controls closely regulating who can manipulate individual files. Administrators would rather create department-level shares and be done with it. Furthermore, businesses would rather install added storage quickly and easily with a reduced amount of administration and capital cost.

In the larger corporate world, true network arrays are often found in the form of Compaq SmartArrays, Sun array clusters, Fibre Channel arbitrated loops (FC-AL), and fiber distributed data interface (FDDI) attached network storage devices. These are the ultimate RAID systems, affording the best that network storage has to offer, but with the high cost normally associated with these types of storage systems.

To combat these massive storage systems, Maxtor Corp. has a new line of NAS units that uses Ultra DMA drives from its DiamondMax Plus 7200 rpm units, which tap the Dual Wave technology to form the MaxAttach series. We reviewed the MaxAttach 4000 chassis for this article, which sports an HTTP Web interface and is network-attached at 100 Mbps Fast Ethernet speeds.

Maxtor units come in three flavors: a single 40-GB unit, a pair of 40-GB drives for mirroring, and the top end Model 4000 unit, which has four 40-GB drives for spanning and mirroring. Our test unit, with four 40-GB drives, gave us a single volume of 72 GB of available storage on a RAID-0/1 configuration. The unit occupies one rack unit of space. Maxtor is preparing to release the next generation of MaxAttach using brand-new, 62-GB drives.

The unit is run by a P55C Pentium processor, 128 MB of memory, and a flavor of the XENIX imbedded operating system that supports Server Message Block (SMB) and Network File System (NFS) protocols for file sharing. When we captured network traffic from the unit, the sniffer told us that LAN Manager 3.1 SMB traffic was seen, and that the SMB shares were being reported as Windows NT Server 4.1 compatible shares when viewed from a Windows 98 client. The unit has dual internal power sources cross feeding to the drives, which means no two drives can overload one power source. In full operation for over one day, no exterior part of the unit was warmer than lukewarm to the touch.

We installed the chassis in our test network hosted by Cisco switched and routed backbones, which use RFC-1918 addresses that tap Network Address Translation (NAT) to connect to the public Internet. This is a switched 100 Mbps Ethernet network connected to three Windows NT Servers with a domain configuration and one Novell NetWare Intranetware 4.11 server.

Our test scenario included breaking up MaxAttach's single large volume into a pair of spanned disks, a pair of mirrored disks, and then four individual disk drives. We then recombined the disk into the single virtual volume that the system ships out to test the device’s ability to handle RAID striping during normal operations.

We also prepared a data set of multiple gigabits of information to flood the device and test its ability to handle multiple concurrent users. The device comes with a XENIX imbedded network operating system, so we set up an FTP test to simulate external users gaining access to the device from the Internet.

The installation process was simple and quick: We had the unit configured and operational using MaxAttach’s internal user security within 10 minutes. All you need is one RJ-45 jack connection into a 10 Mbps or 100 Mbps hub or switch and one rack unit of space. The unit defaults to running as a DHCP client presuming that a DHCP server exists. But should a DHCP server not exist, the unit will activate its own DHCP server running on the 192.168.1.xx subnet. The unit correctly recognized our internal 192.168.0.xx network, and cooperated as a DHCP client.

Coming in at 18.5 inches wide and about 20 inches deep, make sure sufficient clearance exists on your desk or rack without damaging cables. The installation documents clearly state to let the array complete the initial build if you’re worried about using the unit right out of the box. We didn’t wait on it to complete, and had no problems doing so. The unit does run a bit slow while this build process was going, so we decided to give it time to complete the build before forging ahead.

The second phase of the installation took about 30 minutes, including several five-minute periods of reboots while configuration changes took effect. The unit allowed us to change it from a DHCP client to a statically assigned IP address that we assigned and put it in our DNS server. We then set up the device’s IP address in the router’s NAT table for access via the public Internet for testing the FTP server. Other miscellaneous settings included SNMP management, defining an e-mail server and address for the unit to send notifications, and setting the date and time zone.

We then configured the device to use the existing NT domain for authenticating users. This is where we encountered our only bug. To configure the unit to use pass-through NT domain security instead of MaxAttach’s internal user security, you have to change the configuration settings so the unit points to the primary domain controller (PDC) by way of the PDC’s NetBIOS name and the PDC’s IP address. When we did this, the unit pulled down the user and group account listing from the PDC.

On our second pass through doing this, we broke the unit. Instead of putting in the NetBIOS name, we put in the registered domain name system name. This promptly sent the unit to La-La Land. It rebooted, saw the NT domain previously assigned, but no one -- even the administrator -- could attach to the unit. All attempts resulted in the unit rebooting on us and repeating the process.

We called Maxtor’s technical support department, and they confirmed the bug. Out of all the volumes of units shipped to date, we were only the second unit to have encounter this problem. Our combined efforts found an invalid field entry where the NetBIOS name of the PDC is entered. To repair this problem we activated a special process as defined by Maxtor’s product support department that resets the unit to factory defaults. Then we were able to rebuild the device’s configuration or restore a saved configuration. This worked perfectly after we duplicated the bug. The bug fix should now be generally available, so it is not an issue for future production units.

We feel compelled to make an important distinction with the use of RAID in this system. Many owners of this system may feel the urge to break the disk array into four individual disk drives to gain higher storage. You can do that, but you will lose the advantage of RAID protection. Also, if you have to do this special restoration process, the factory default that the unit is returned to is a full-spanned and mirrored array. If you were using four individual drives, then you would lose all of that data as the array is rebuilt. If this restoration procedure must be executed, however, then chances are the data will be inaccessible anyhow.

The remaining parts of the installation completed without incident. We created both SMB and NFS shares for our test clients and assigned share-level security including new domain groups.

We had a bit of fun testing the unit’s ability to sustain multiple users, both locally and via remote access. As expected, the 100 Mbps Fast Ethernet connection was a bottleneck. On a switched network, the unit supported 28 concurrent connections without dropping a single packet of data. It was slow, however as we filled the pipe with 28 streams of data at full throttle.

We then created other shares for users and for an FTP site. Accessing the unit from the public Internet, we performed standard FTP actions to the unit without problem. We should note that the FTP server reported back as a Unix L8-type server, confirming the use of some form of Unix/XENIX as the imbedded NOS. All FTP actions were completed without problem, but we didn’t see any facility to log FTP actions such as a syslog or ODBC redirection. Maxtor confirmed that while this is a useful tool, its implementation raises the cost of the unit above its target as the marketplace of choice. We agree. Most SOHO or small businesses that would use MaxAttach probably wouldn't have Unix servers or an Oracle or SQL Server database in operation.

As mentioned, the unit is administered via a browser to the unit’s internal HTTP Java server, but you cannot administer the unit remotely unless you permit NetBIOS traffic through the firewall. Any browser that supports Java 1.1.4 or higher should be able to administer the chassis. This is a double-edged sword: you can’t administer the unit without opening a security hole, but remote administration is a nice option to have. This is not a problem with Maxtor, just a fact of networking life.

Creating shares is done via the MaxNeighborhood administration tool, and includes applying the proper user and group-level permissions. You’ll be able to grant or deny access based on any of these security options, which is sufficient for 90 percent of all situations. We discovered that NT domain administrators who browse the device via NT’s network neighborhood or the Windows Explorer cannot create or administer shares: MaxAttach does not support SMB requests as a security measure. You can, however, map a network drive to the shares without problem. You can alter your normal network user login scripts and policies to access MaxAttach shares as you would for a server-based share.

We further tested the device on our network management platform, CiscoView and HP OpenView. SNMP operations were completed as expected, so we had faith that the unit had merged in with our normal network operations without issue. We also added the MaxAttach shares to our Veritas BackUp Exec system backup plan, which backed up the data as if it was any other NT server share. Veritas saw no distinction between MaxAttach and an NT Server -- it reported a NetBIOS server and worked fine.

Finally, we addressed the physical device itself. How often are new drives coming out, every six or nine months? Our unit is an example of this issue -- we received four 40-GB drives, yet newer DiamondMax Plus 62-GB units are now on the streets. We asked Maxtor about its upgrade policy for the newer drives, and no such policy exists at this time. Why should I replace the entire chassis when just swapping out four drives and restoring the data is all there is to it?

Maxtor says this is a "no user serviceable parts inside" situation. By the time a MaxAttach device -- regardless of model -- fills up, drive capacity will double again and newer MaxAttach units will be out. More often than not, it is cheaper and safer to add a new chassis rather than add new disk drives and have old drives lying around gathering dust.

Still, those who know how to swap out drives should be allowed to do so instead of adding a new chassis. What if the user didn’t have more rack space to add a second or third unit, nor could they afford the time to send an existing unit back to Maxtor for an upgrade? Would such a user-based upgrade violate the Maxtor warranty? These are all business and support decisions for Maxtor -- and the user -- to consider.

Overall, there is little to complain about and lots to like about the Maxtor unit. It solves the need for quick and easy storage addition to the network, eases administration, and significantly reduces the cost of adding storage. We’re well aware that other RAID storage solutions exist that are more full-featured than MaxAttach, but they also carry the related hefty price tag. We found Maxtor's unit to be easy to administer because the burden is much less than owning a separate distinct server.

The diminutive size of the chassis belies the product's usefulness and purpose: simplified network storage with a small price tag. We think most businesses -- large and small -- will find a place in their networks for the MaxAttach chassis.

[Infobox]

MaxAttach 4000 NAS
Maxtor Corp., Milpitas, Calif.
(408) 432-1700

www.maxtor.com

Price:
Model lists for $3,995, but mail order process found as low as $3,245.

+ Small rack size

+ Easy to install and manage via Web browser

+ Simple and effective NT domain integration

+ Fast drives and network connectivity

+ Good tech support

- No upgrade plan to larger drives

- Lacks NTFS security