Netgear SC101 SAN Device: Introduction

The Netgear SC101 Storage Central is a small, consumer level SAN (Storage Area Network) device designed for home users and based on the ZSAN SAN protocol. ZSAN by Zetera is a competing, but far less common, SAN protocal with iSCSI. The device is small and attractive – it should probably have been called the Storage Toaster.

The SC101 uses one or two Parallel ATA (PATA, UltraATA, IDE, EIDE) drives. When using two drives the drives can be mirrored (RAID 1) for data protection. With just a single drive there is no drive failure protection. The unit has a single 100Mb/s FastEthernet connection.

Because the SC101 is true SAN it would be unable to share data between separate computers if Windows’ standard NTFS file system was used. To allow for this functionality Netgear provides the Shared File System or SFS. In the current release the filesystem has been renamed DataPlowFSZ.

Because of the use of DataPlowFSZ there are some severe limitations in the usability of the SC101. The most important is that DataPlowFSZ does not support NTFS ACLs. That means that by placing files onto the SC101 you are making them available with complete read and write access to anyone that can attach to the device on the network. The normal security system with ownership and levels of permission based on your Windows user account is non-existant on drives mounted from the SC101. For anyone wanting to protect sensitive data this could be a real concern and will certainly limit the potential for this device to be widely used by small businesses.

I have attempted to format the SC101 using NTFS but it is not possible at this time. Complete block level access to the device is not given to the operating system when using the Zetera/Netgear drivers. Only DataPlowFSZ is available for use.

The SC101 is supported on Windows® 2000(SP4), XP Home or Pro (SP1 or SP2), 2003 (the site lists SP4 but since that doesn’t exist I will assume that they meant SP1.) Recent software updates also make the unit available for Windows Vista.

My Initial Setup (SFS)

I installed two Seagate Barracuda 7200.10 500GB PATA drives into my new SC101, plugged in the power and attached the network cable to my DHCP enabled network. My home network is based on a Netgear ProSafe FVG318 which is an integrated router, switch, wireless and VPN unit. I do not have Gigabit Ethernet (GigE) networking on my switch.

My home computer is Windows XP Pro SP2. To set up the SC101 you need to install the Storage Central Management Utility or SCM. The SCM software that came with the unit was uninstallable but I went to Netgear’s website and downloaded the latest version which installed without any issues. The SCM fired up and it immediately detected the SC101 on my network. It detected the unit’s firmware revision, determined that it was too old to work with the new version of SCM and offered to automatically bring the SC101 up to date. I selected to do so and we continued. It took a few minutes for the firmware upgrade process to complete. When it was finished the SC101 rebooted.

Initially the SCM Utility was unable to see any space on the newly installed drives. I was forced to go through the “Advanced” path within the utility and select “refresh” which suddenly showed the available space on the disk. I then went back and used the Smart Wizard utility to create my first disk. I chose to allocate 400GB from each physical drive as a mirrored set with sharing enabled but without passwords enabled.

One of the first oddities about the SC101 that I noticed is that the unit automatically allocates two IP addresses – one assigned to each physical drive. The actual process of mirroring the drives is handled by software on the computer and not within the unit itself. This, I am sure, makes the unit much less expensive to produce however it causes lowered performance because of network traffic. It does lend itself to interesting theories as to additional uses for the unit. If attached to a Windows Server OS I assume that mirroring could be handled by the OS RAID software instead of the proprietary Zetera software. Two units could be combined for RAID 5 or RAID 0+1 / 1+0 because each drive is seen as an independent drive resource.

The disc creation utility automatically attached the newly created mirrored drive to my system as drive F: (mileage may vary.) I was immediately able to begin copying data to the SC101 for backing up.

At the end of my first day with the Netgear SC101 the unit is working as advertised without any real problems. I hope to investigate more advanced functionality that can be squeezed out of this unit. I am especially looking forward to attempting to attach this unit to a Linux workstation.

My initial tests with the unit show that access to the drives over the network is extremely slow. But as the unit is primary used for backup the performance is adequate and will not cause problems for normal users. If you are accessing small files off of the drive such as documents or pictures you won’t notice the speed issues at all. Moving large files can be painful.

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