Build your Own NAS Box

NAS (Network Attached Storage) is an answer to today’s business requirements of ERP, MIS and databases, where data has to be accessed by multiple users, both internal and external. NAS is a stand alone, dedicated, high-speed communicating machine that has its own OS and software and is connected directly to the network. 

You can get NAS solutions from big companies such as HP, IBM, Dell, at equally big costs. Or, you could read this article and use ordinary hardware to build a NAS appliance server yourself. We will build a NAS appliance with a storage capacity of more than 1 TB (1TB =1024GB). It will have several features of commercial NAS solutions and will be capable of easily supporting 250-300 users. And, we refer to this solution as PCQ NAS.

PCQ NAS: components needed

To set up PCQ NAS, we used the following components. 

• Intel 865GBF motherboard which has 
• Two IDE connectors to connect up to four PATA (Parallel ATA) disks
• Two SATA (Serial ATA) connectors for two SATA disks
• Gigabit Ethernet port for fast communicationl 512 MB RAM
• Intel P4 3.0 GHz CPU (you could use a slower processor as a NAS device is not required to do many compute-intensive tasks)
• Up to six disk drives. (If each drive has a capacity of 180 GB, with six drives you will get 1080 GB, which is 1.05 TB.)*
• Windows 2000 Server. This will have IIS and Terminal Services running in Remote Administration Mode
• Windows Server Appliance Kit 2.1 (download from Microsoft’s website) and MS Storage Resource manager for server appliances (180-trial version. Download form Microsoft’s website.) 

*You will need power connector multipliers to connect six disk drives as most motherboard power supplies come with only four connectors. These multiplier connectors are easily available.

PCQ NAS: Features

The PCQ NAS solution incorporates most features that you would find in a commercial solution. These features are:

RAID-5 Remote Management (Web interface) Heterogeneous client support Ease of integration Back-up and restore functionality

For disk hot swapping, a feature that we have not included, you need a PCI-based IDE card that supports hot swapping of disk drives.

Disk management and RAID

For better performance and reliability of data, disk drives should be configured as RAID (Redundant Array of Independent Disks). RAID level 5 is most suitable for NAS devices as it provides performance improvements for disk I/O as well as fault-tolerance against single-disk failures. A minimum of three disks are required for RAID 5, so we can easily configure the six disks of our PCQ NAS under RAID 5. With a RAID 5 volume, some disk space is used to store parity information of the data on the array. Hence the total storage space available becomes S * (N-1), where S is the storage capacity of each disk and N is the number of disks. In our setup the total capacity with RAID 5, will be 180 * (6-1) = 900 GB.

To create a RAID 5 volume, first convert all disks to dynamic disk using the Windows Disk Management tool. Next, create a new volume and set its type to RAID-5. Select all disks that are going to be part of the array. After this, format the volume and assign it a drive letter. All disks in the array will be a part of a single volume and will appear under a single drive. Once this is completed, array regeneration will take place, which is a long process, but you will be able to use your volume during this process. However, the volume will be fault-tolerant only after the regeneration of array is complete. After this even if one disk goes faulty, you data is
still safe.

Remote management

After disk management, remote management and monitoring is what everybody would like to have in a NAS appliance. For this, we will use the MS Server Appliance Kit, a toolkit to build ready to use appliances, which provides browser-based management features through
IIS. 

It is very easy to install the Server Appliance Kit. During installation, just select ‘Network Attached Storage (NAS) Appliance’ in the ‘Select the type of appliance’ window and your appliance is ready to use.

After the kit is installed, it’s time to use it. The kit installs all management features over IIS, so just access your NAS device in Web browser at port 8099 from any client, give the administrative password and you will be connected to the Web interface of the appliance. The Web interface provides all the features you require for managing the NAS device and you can disconnect the local display altogether.

Some prominent features that you will get from the Web interface of PCQ NAS are: the management of disks, shares, users and network interfaces; the configuration of machine identification, domain memberships, backup, date/time setup, shutdown, reboot and e-mail alerts.

Heterogeneous file serving

A typical network has different types of clients and a NAS device should be able to support all of them. Windows 2000 has built-in file sharing services for Apple Macintosh clients; for UNIX and Netware shares, you need to install SFU (Services for UNIX) and Services for Netware, respectively. After the Services for UNIX and Netware are installed, you can create UNIX (NFS) and Netware shares. The Web interface of the appliance lets you create heterogeneous shares from a single point. The different types of shares that you can define with the appliance kit are Windows (CIFS), Unix (NFS), AppleTalk, Netware, Web (HTTP) and FTP. This capability makes your NAS box extremely useful in a heterogeneous network. 

Integration into existing infrastructure

You would also like to integrate the NAS device with your existing network setup. You can make NAS, running Windows 2000, a part of Windows 2000 Active Directory Domain. This way the NAS box will support the existing network users and various file restrictions can be applied to them for the NAS server. All these settings are available from the Web interface.

Using Services for UNIX, NIS domain users can be mapped to Windows usernames. SFU needs to be configured separately for that.

Directory quota, file screening, storage reports

Windows 2000 has disk quota support built-in, but does not let you apply directory quota restrictions by default. MS Storage Resource Manager for Appliance Kit provides this feature also. A 180-day trial is available on Microsoft’s website. The installation of the storage manager is very simple and after the installation, three more features are added to the NAS device.

Directory quota lets administrators enforce space utilization restrictions on directories and send e-mail alerts to inform users and administrations about quota violations. File screening helps you control which types of files are allowed on the server.

Storage reports provide comprehensive information about File Type Summary, Directory Quota Usage Summary, Large Files, Files Not Being Backed Up, etc. All these features make administration and management of the NAS device simple and easy.

Back up and restore

Although most backup devices come with a SCSI interface, some also come with a USB interface. For example, Sony StorStation AIT (Advanced Intelligent Tape) drive has a USB interface. Almost all motherboards come with USB ports, so you can easily use a USB backup device. In addition, with scheduled backup settings, the NAS device can take file backups without any manual intervention.

Anoop Mangla