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NETGEAR ReadyNAS Ultra 4 (4-bay, 4TB: 2 x 2TB) Network Attached Storage, latest generation RNDU4220

by Netgear
30 customer reviews

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  • Blazing fast performances for bleeding-edge applications
  • Best software partnerships to provide best store and serve user experiences
  • First TiVo compatible DVR network archiving and storage device storage device
  • Continuous backups from PC/Mac with Memeo Premium Backup
  • Built in iTunes Server

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Product Description

Product Description

The NETGEAR ReadyNAS Ultra series deliver the power you need to run bleeding-edge applications and the flexibility you want to store, share and protect your prized multimedia collections. Two Gigabit Ethernet Ports deliver ultra-fast connections, while three USB ports offer the flexibility for users to connect other devices with a USB connection (e.g., printer servers, external USB storage devices or digital cameras). These multimedia desktop storages are ideal for media enthusiasts with large digital media libraries who want to take their media files wherever they go. X-RAID2 - Manage volume expansion automatically as you add new hard drives or replace existing drives with larger capacity drives. ReadyNAS Remote - Get secure drag-and-drop remote access without complicated network setups. ReadyNAS Vault - Backup critical files off-site for added security and peace of mind, then access and restore them remotely online. Rsync - Replicate and synchronize files between two ReadyNAS devices. TiVo compatible - Archive your favorite television programs and play them back to any TiVo DVR in your home. Media shifting with Skifta - Access multimedia content from your ReadyNAS while you’re away from home on connected DLNA devices. Transcoding with Orb - Convert multimedia content for optimal streaming on mobile devices. Automatic backups - Back up three computers (PC or Mac) continuously using Memeo Premium Backup and restore any previous version of a file with a simple right-click.

From the Manufacturer

NETGEARReadyNAS Ultra 4 (4TB: 2 x 2TB)RNDU4220

Affordable Storage and Media Streaming Solution

The ReadyNAS Ultra Family is a series of powerful network-attached storage (NAS) with built-in media server capabilities that allow advanced home users to store, share, and protect their digital assets with confidence. These home media servers are ideal for users with large digital media libraries who want to take their media files wherever they go. ReadyNAS Ultra is designed specifically for advanced media users in home and small business environments.

The NETGEAR Difference – ReadyNAS Ultra 4
  • Reliable data backups for all networked devices
  • Local and remote streaming
  • Continuous on and offline data protection
  • ReadyNAS Remote – Access files from mobile device
  • ReadyNAS Vault – Store files to the cloud
  • Plex Media Server – Local and remote media streaming


  • Easy-To-Use – Complete set-up in less than 8 clicks
  • Expandable – Easily add capacity on-the-fly
  • Worry Free – Automatic RAID management and migration tool


  • Backup Speed – Built for optimum read/write speeds
  • Streaming Speed – Media streaming up to 140% faster than home NAS peers
  • Powerful – Transcoding capable for streaming on-the-go


  • App Library – Ever expanding list of applications (
  • Unmatched Support – 24x7 support and 3-year warranty
  • Market Leader – #1 network storage vendor in the world
ReadyNAS Awards and Recognition
ReadyNAS Ultra 4
Front and back view
ReadyNAS Ultra 4 front and back view
Open view
ReadyNAS Ultra 4 open view

Choose the right ReadyNAS

ReadyNAS NV+ v2 and DuoReadyNAS Ultra and Ultra PlusReadyNAS Pro
 Duo v2
NV+ v2
Pro 2
Pro 4
Pro 6
 Affordable network storage for the home with standard media sharing and backup features.Advanced home and home office network storage with advanced media sharing and backup features.Business class network storage for server/workstation backup or extra capacity for application servers.
Supports 1TB & 2TB SATADuo v2: 2-bay
NV+ v2: 4-bay
Ultra 2 & Ultra 2 Plus: 2-bay
Ultra 4 & Ultra 4 Plus: 4-bay
Ultra 6 & Ultra 6 Plus: 6-bay
Pro 2: 2-bay
Pro 4: 4-bay
Pro 6: 6-bay
Ports(1) Gb LAN, (1) USB 2.0, (2) USB 3.0(2) 1Gb LAN, (1) USB 2.0, (2) USB 3.0, iSCSI Support(2) 1Gb LAN, (1) USB 2.0, (2) USB 3.0, iSCSI Support
Disk ManagementReadyNAS X-RAID2, JBOD, RAID 0, 1ReadyNAS X-RAID2, JBOD, RAID 0, 1, 5ReadyNAS X-RAID2, JBOD, RAID 0, 1, 5, 10
CPU1.6 GHz Marvell single-coreUltra: Intel Atom single-core
Ultra Plus: Intel Atom dual-core
Pro 2: 1.8 GHz Intel Atom Dual Core
Pro 4: 1.66 GHz Intel Atom Dual Core
Pro 6: 2.66 GHz Intel Atom Dual Core
Memory256 MB1 GB1 GB
RAIDiator for simple set-up, configuation and monitoringyesyesyes
Photos II for easy photo storage and sharingyesyesyes
Memeo premium backup licenseyesyesyes
ReadyNAS Remote for secure iOS or Android access yes* yes* yes*
BitTorrent for peer-to-peer downloading yes* yes* yes*
ReadyNAS Vault for backup to the cloud  yes* yes*
Media shifting to DNLA devices/consoles  yes* yes*
Mobile transcoding for media streaming to iOS/Andriod  yes* yes*
ReadyNAS Replicate for easy off-site disaster recovery  yes* yes*
Back-up TiVo Content  yes* yes*
Warranty Terms3 years3 years5 years

*Available as software download through

Technical Specifications

  • NETGEAR RAIDiator Operating System
  • Setup Wizard and easy browser-based interface
  • Integrates with Active Directory users and group authentication
  • Intel multi-core processor
  • Fully managed dual 10/100/1000 Ethernet ports for link aggregation and failover
Supported Web Browsers
  • Internet Explorer 9.0+
  • Opera 11.0+
  • Safari 5.0+
  • Mozilla Firefox 4.0+
  • Chrome 11
Backup Schema
  • Client backup target using CIFS, NFS, FTP or HTTPS
  • Integrated Backup Manager for full and incremental ReadyNAS backups
    • Snapshot support for point-in-time backups of the ReadyNAS system
    • Backup to/from USB disks
    • Remote backup to CIFS, NFS, FTP and HTTPS targets
    • Remote backup to another ReadyNAS via rsync and secure rsync
  • System configuration backup and restore
  • Multi-system cloning
Included Backup Software/option
  • Support of Symantec Backup Exec agent (RALUS license required)
  • Acronis ABR10 Virtualization Edition and Advanced Workstation Edition (unlimited license free for 90-days with registration)
  • ReadyNAS Replicate
    • Secure replication software with online unified management
    • Free trial license for 45-days with registration
    • Perpetual license available for purchase. part number: RN00RPL1
  • ReadyNAS Vault cloud-based online backup
    • Optional service
    • 30-day free use included
  • NETGEAR 5-year Warranty†
ProSupport Service Packs Available
  • ReadyNAS Pro 2
    • OnCall 24x7, Category 1: PMB0331
    • XPressHW, Category 1: PRR0331
  • ReadyNAS Pro
    • OnCall 24x7, Category 2: PMB0332
    • XpressHW, Category 2: PRR033
  • ReadyNAS Pro 6
    • OnCall 24x7, Category 3

Product Information

Expand all Collapse all Technical Details
Brand NameNetgear
Item model numberRNDU4220-100NAS
Operating SystemRAIDiator
Item Weight20.9 pounds
Item Dimensions L x W x H8.90 x 11.20 x 12.90 inches
Color Black
Processor Count1
Power SourceAC 100 - 240V, 50/60 Hz
Additional Information
Best Sellers Rank
Shipping Weight15.2 pounds
Domestic Shipping Item can be shipped within U.S.
International Shipping This item is not eligible for international shipping. Learn More
Date First AvailableJuly 12, 2010
Warranty & Support Return Policy: You may return any new computer purchased from that is "dead on arrival," arrives in damaged condition, or is still in unopened boxes, for a full refund within 30 days of purchase. reserves the right to test "dead on arrival" returns and impose a customer fee equal to 15 percent of the product sales price if the customer misrepresents the condition of the product. Any returned computer that is damaged through customer misuse, is missing parts, or is in unsellableRead more condition due to customer tampering will result in the customer being charged a higher restocking fee based on the condition of the product. will not accept returns of any desktop or notebook computer more than 30 days after you receive the shipment. New, used, and refurbished products purchased from Marketplace vendors are subject to the returns policy of the individual vendor.

Product Warranty: For warranty information about this product, please click here

Customer Reviews

Most Helpful Customer Reviews

31 of 32 people found the following review helpful By Bruce E. Wampler on November 26, 2010
Style Name: ReadyNAS Ultra 4, Diskless (0TB) Verified Purchase
It has been a while since I've gotten a new NAS system, and I am totally impressed with this unit. It has been almost totally painless. Now all the computers at my house can have plenty of backup storage, and easily share all the data, video, photo, and music files you are likely to have.


I am a Computer Engineer - been in the field for 35 years, so I'm fussy about my hardware. I have a house hardwired with CAT5 plus a WiFi router. The main machines are Macs, but there are some Windows computers too. This unit supports Time Machine - and the support works perfectly and painlessly. I also have a couple of DLNA media devices, so that is an important feature. The ReadyNAS also lets you plugin USB drives and they instantly become available on the network as well - so all my old external USB drives are not useless with this upgrade.

THE GOOD (Great, actually)

* This device is as close to plug and play as I've seen in a long time. There is a somewhat lengthy setup - but we're dealing with Terabytes of disk space that has to get organized and set up properly for the X-RAID striping.

* You can plug in new drives to expand capacity as needed.

* Works seamlessly on a mixed Mac/Windows/DLNA media environment

* Redundant storage keeps going even after a single disk failure. I feel all my photos and videos are now safe (although I still keep an extra off-site backup, just in case.)

* Fast - almost as fast as a directly connected USB, but now available to all the computers in the house.

* Can install extra software to securely access your data from the web anywhere.


* There is a setting on the Network Interfaces called MTU.
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15 of 15 people found the following review helpful By Royal on March 30, 2011
Style Name: ReadyNAS Ultra 4, Diskless (0TB)
I'm a network engineer and I chose the diskless because I wanted to control my drive specs.

In general avoid power-saving, "green" drives. There have been a lot of issues and power-savings translates into slowdowns managed by the drive's internals. Similar to how CPUs lower power consumption and heat by slowing down. If you want speed, green is not a "go".

I bought 2 x 2tb 64mb cache drives. I have a third, same spec at home, which I need to migrate data off first.

I plugged the Netgear into the Verizon FIOS wireless router(six 100Mb LAN ports) and my laptop was plugged into this. I transferred 500 Gb of data to the netgear and it sustained just about 80 mbps network transfer rate across the network. That's about what you can hope for on 100MB. Depending upon switch & pc hardware and transfer protocol I have seen higher, but often highspeed transfers max out at the 80% mark. Once I bring a gig switch to the house I'll see if I can push further. At some point I will max out read or write. Just not sure when and whose limits.

The Apple streaming support is there. I-Tunes found my 20,000 song library on the netgears. My shares automatically showed up on Macs. Windows mapped without issues. None of the playlists work anymore though. And information is missing or wrong. DLNA worked, but I don't have a good DLNA client. I think my blueray player may have some capability there. I'll update once I get it wired up to the network. I don't have a TIVO to test out Tivo support as well.

Unlike complaints of the lower end model, the admin interface on the Ultra is quick and responsive. I showed the unit to an earlier model ReadyNAS owner and they see a big difference.
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7 of 7 people found the following review helpful By B. Nicodemus on April 18, 2012
Style Name: ReadyNAS Ultra 4, Diskless (0TB)
I've had the ReadyNAS Ultra 4 for over a year and it has operated flawlessly. Started w/ 2 drives and once they were full popped in a third unformatted disk and it was automatically formatted and data re-striped without incident. Last week my 3 drives reached capacity and I popped in a 4th which was automatically formatted and all 4 drives again re-striped without incident. With the current firmware, you can now plop 4 3TB drives in this box (12TB total raw capacity). With conventional mirroring, that would give you 6 TB of fully redundant capacity. With Netgear's XRAID striping technology you actually would get around 8.25TB of fully redundant capacity.

The NAS allows you to configure an email address and it will automatically send you an email when appropriate (e.g. h/w problem, reboot, firmware updates available, nearing full capacity, etc.). I have applied several firmware updates as they have come available and experienced no update issues.

Finally, the ReadyNAS forums are extremely helpful and full of very sharp people that have been very helpful in answering technical questions.
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5 of 5 people found the following review helpful By Will's Mom on January 4, 2011
Style Name: ReadyNAS Ultra 4, Diskless (0TB)
I've been using this unit with 4x 2TB hard drives for four months now, and it has performed flawlessly. The user interface software (RAIDar) is incredibly easy to use, and I had no trouble setting the unit up just the way I wanted it. I use it to share files over a wireless home network with 3 laptops, 2 smartphones, a DLNA TV and a DLNA DVD player. I had no trouble whatsoever getting these devices connected to the NAS.

I especially like the power saving features - I set the unit to turn off at midnight and back on at 7 a.m. No sense leaving it on while I'm sleeping. You can fine-tune this feature to set different on/off times for each day of the week. I also set it to "spin down" the hard drives after 10 minutes of idle time. That way they are resting and not using much power if I'm not on the network.

I also like that the unit will email me with problems or updates about completed backups, etc. It will also communicate with my battery backup so it knows when the power is out and can take appropriate actions to shut down when the battery is low. Finally, there are a lot of add-ons (basically, "apps") that you can download to expand the functionality of the unit. I've found several of these to be useful.

The drawbacks are that this is not a cheap piece of equipment, especially if you add four big drives. I will also agree with the other reviewer who said that the concept of "shares" could be explained better.

The bottom line: I was willing to pay for a reliable NAS that worked well and didn't require constant tinkering to keep working. This NAS fits that description for me. As the saying goes: "Buy quality, cry once; buy cheap and cry often."
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