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September 21, 2007
Eight Port, RAID 6, Bootable, SAS Host Adapter
A Review of the Areca ARC-1680x PCI-Express to SAS RAID Controller
By Arthur Whalem
The ARC-1680x supports a Command Line Interface (CLI) and includes a browser-based management tool for easy configuration. The controller features an alarm and SMTP email notification should a hard drive failure occur. The purpose of this article is to determine how the Areca ARC-1680x will perform with the Apple Mac Pro.
System Requirements
Requires an available PCI-Express slot.
Supports Mac OS X 10.4.x or higher, Windows, Linux and FreeBSD.
Requires external SATA I or SATA II 3.5" hard drives.
Dual external mini-SAS connectors - cables not included.
PCI-Express X8 interface.
SMTP support for email notification.
Optional SAS expander required for use with more than 8 hard disks.
What's Included?
The Areca ARC-1680x PCI-Express to SAS RAID controller includes a PCI-Express host adapter, a 166 page printed users guide and a CD with software drivers and documentation.
InstallationPCI-Express also known as PCIe, communicates using 250MB per second data lanes. PCI-Express bandwidth is determined by the number of data lanes that the device can accommodate. One lane, four lanes, eight lanes, or 16 lanes are some of the typical PCIe configurations available.
The Areca ARC-1680x SAS host adapter is an eight lane controller. The manual does not indicate if the ARC-1680x is compatible with a 4x PCIe slot. However, most 8x PCIe controllers can be used in a 4x slot. The PCI-Express interface simply down shifts to the lower speed. By testing the ARC-1680x in an Apple Mac Pro PCIe 4x slot, it was discovered that the controller will function well in a 4x configuration. The performance difference between using the ARC-1680x in an 8x slot versus a 4x slot was minimal with an eight drive striped RAID set. In these tests the 4x slot provided 1% slower write performance and the same read performance as the 8x slot. However, if the ARC-1680x is used with a larger SAS array the 8x slot results will probably provide a larger performance difference. PCIe slot 4 of the Mac Pro is a good location for installing the ARC-1680x as it is set to 8x by default.
Mac Pro users will need to install the mraid_macpro driver found in the PACKAGES folder on the install CD. The Mac Pro will not recognize the card without the driver installed. AMUG utilized the ARC-1680x Mac Pro SAS beta driver dated September 12, 2007 during this review. It can be found on the Areca ftp site. This driver updates the web manager features for the ARC-1680x. Firmware version 1.4.3 dated 9-6-2007 was also installed along with the ARC1680EFI BOOT ROM that allows Mac OS X to boot from hard drives or RAID sets mounted on the ARC-1680x.
Once the Areca Mac OS X driver is installed the user can open a web browser window to port 81 to configure the ARC-1680x. The browser address is formatted as http://xxx.xxx.xxx.xx:81/ with the computers IP address placed where the xxx.xxx.xxx.xx is listed. If the user is configuring the computer locally the address http://localhost:81/ can be used. The default user name is admin with a password of 0000. Once the web interface is open, it can be bookmarked for easy future access. Clicking on the "Quick Create" menu within the web interface provides an easy method for establishing RAID 0, 1, 3, 5, 6 and 10 configurations.
The ARC-1680x also allows users to create RAID 30, 50 and 60 configurations. To do this, use the "Create RAID set" menu to setup two equal sized RAID sets. Next, use the "Create RAID30/50/60" menu to configure the RAID 30, 50 or 60 disk array.
If the Mac Pro user would rather utilize Disk Utility to configure hard drives attached to the ARC-1680x, the web interface can be used to set the card to JBOD mode. Clicking on the "System Configuration" menu and setting the JBOD/RAID setting to JBOD allows Disk Utility to work individually with each of the hard drives mounted on the ARC-1680x.
When the ARC-1680x is set to JBOD mode all of the controllers RAID features are disabled and the hard drives are managed by the operating system. As most users will purchase the ARC-1680x for its SAS and awesome RAID capabilities they will probably want to leave the card in RAID mode. However, it is nice to know that hard drives connected to the ARC-1680x have the ability to be controlled directly by Mac OS X or the ARC-1680x RAID engine.
The Apple Mac Pro has four PCI-Express slots. It utilizes the "Expansion Slot Utility" to configure the speed of the PCIe slots. The Expansion Slot Utility can be found within Mac OS X at Macintosh HD: System:Library: CoreServices: Expansion Slot Utility. It will usually automatically launch when it detects that a card has been installed in a slot that is slower than the cards maximum speed.
When the ARC-1680x is installed in slot four of the stock Apple Mac Pro 2.66 GHz the Expansion Slot Utility menu looks like the image above. The Mac Pro automatically defaults to eight lanes in this configuration. Users can open the Expansion Slot Utility if they want to verify that the ARC-1680x is mounted in an eight lane slot.
In the Mac Pro system profiler window above, PCIe slot 4 is shown. The Areca ARC-1680x is displayed in the window as a RAID Controller with a card name of "pci17d3,1680".
Cable Options
The Areca ARC-1680x provides two external mini-SAS connectors that can be configured with several different cable options. The Areca ARC-1221x also uses these same connectors. As a result, data cables that work with the Areca ARC-1221x will also work with the Areca ARC-1680x and visa versa. The mini-SAS connectors allow the host adapter to accommodate a wide range of SAS and SATA enclosure solutions. While the ARC-1680x does not support SATA port multiplier enclosures, it does support SAS expanders and direct connect SATA enclosures. Cables are purchased separately based on the users enclosure configuration. Some of the available cable options include:
1) External mini-SAS to Infiniband (Screw) for Multilane enclosures $33.
2) External mini-SAS to eSATA (I connector) for eSATA enclosures $59.
3) External mini-SAS to SATA (L connector) $44.
To access all eight SAS ports on the ARC-1680x, two external mini-SAS cables are required. The external mini-SAS to Infiniband cable model Ext-MS-1MSB
provides a mini-SAS connector on one end and an Infiniband multilane type connector on the other end. These cables allow the ARC-1680x to connect with a multilane SAS or SATA enclosure. The EnhanceBox E8-ML SATA/SAS Multilane 8-Bay enclosure ($595) provides dual multilane connectors which makes it a nice match for the ARC-1680x. This setup allows all eight hard drive bays inside the E8-ML enclosure to be connected using two data cables. Many of the new SAS enclosures with internal expanders will also utilize this cable. During the review, AMUG tested the Areca ARC-1680x SATA host adapter with this type of cable and the EnhanceBox E8-ML.Another cable configuration that may be used with the ARC-1680x is the external mini-SAS to eSATA (Type I connector) cable for eSATA
enclosures. These cables allow the ARC-1680x SAS host adapter to be connected to any direct connect eSATA external enclosure. The model number for this cable is Ext-MS-1MES. ARC-1680x users will need two cables to support all eight SAS ports. Enclosures that will work with a direct connect eSATA data cable include the FirmTek SeriTek/2eEN4 eSATA 4 bay enclosure, the Addonics Disk Array with dual Disk Array 3SA, the Sonnet Fusion 400, the WiebeTech SilverSATA IV SJ 4-bay enclosure and many others. Basically, any SATA enclosure that uses eSATA data connectors and does not have a port multiplier will function with the ARC-1680x and the mini-SAS to eSATA model Ext-MS-1MES cables.Features
The Areca ARC-1680x Serial Attached SCSI (SAS) RAID controller supports both SATA and SAS hard drives along with SAS expanders, SAS enclosures and SATA direct connect enclosures. This feature allows existing SATA users to upgrade to RAID 6 redundancy while also supporting SAS hard drives and SAS expanders as storage requirements increase. The ability of the SAS controller to support both SATA and SAS interfaces provides users with several configuration options.
The eight port ARC-1680x is powered by the Intel IOP348 I/O processor. This chip integrates an I/O processor with a SAS/SATA I/O controller, combining RAID and SAS technologies. The ARC-1680x utilizes an 800 MHz version of the Intel IOP348 I/O processor with 256 MB of on-board DDR333 533 MHz SDRAM memory with ECC protection. The processor utilizes approximately 11 watts of power. Areca provides a heat sink with a cooling fan that enhances processor cooling while maintaining the quiet operation of the Mac Pro. The ARC-1680x combines an 8-port 3Gbps SAS/SATA controller with hardware RAID 5/6 acceleration. By off loading RAID calculations from the host CPU to the ARC-1680x, overall system performance can be improved.The Areca ARC-1680x RAID engine provides high performance and high reliability. It supports RAID levels 0, 1, 3, 5, 6, 10, 30, 50, 60 or JBOD. RAID 6 offers fault tolerance greater than RAID 1 or RAID 5 while utilizing the capacity of two disk drives for distributed parity data. Data is first striped on a block level across a set of disk drives. Next, a second parity set is calculated and written across all of the hard drives. This process allows RAID 6 to provide a high level of redundancy that can recover even with two simultaneous hard disk failures.
The Areca ARC-1680x PCI-Express 8x interface can be used to mount up to eight SAS/SATA hard drives in a direct connect configuration. In addition, SAS expanders can be used to support up to 128 devices. The controller provides write-through or write-back cache support, array roaming, online RAID level/stripe size migration, online capacity expansion & RAID level migration simultaneously, online volume set growth, instant availability and background initialization, automatic drive insertion / removal detection and rebuilding, hot swap, SMART (within browser), NCQ, staggered spin-up, alarm buzzer, SMTP support for email notification and provides upgradeable firmware. When the ARC-1680x is upgraded using the ARC1680EFI BIOS it provides Mac OS X boot capability. Drivers are available for Windows 2000/XP/Server 2003, Linux, FreeBSD, Novell Netware 6.5, Solaris 10 X86/X86_64 and Mac OS X. The Areca ARC-1680x comes with a CD and an in depth manual.
Not Supported
No Traditional SMART Support - While the Areca web interface can be configured to display SMART data, the driver does not pass this information to Disk Utility. As a result, Disk Utility will indicate that SMART is not supported on any volume connected to the controller. Users will need to use the Areca web interface for monitoring SMART data.
No Traditional Sleep Support - the Mac Pro can utilize sleep mode if the ARC-1680x is installed and no hard drives have been powered on it. However, if a RAID or an individual hard drive is attached or has been attached during the current power cycle the Mac Pro will not sleep properly. Restarting the computer with no hard drives powered will allow sleep mode to function once again.
Energy Usage
According to the Kill-a-Watt electricity usage monitor, the Areca ARC-1680x controller requires approximately 13 watts while idle when installed in a Mac Pro 2.66 GHz model. This was determined by measuring the energy usage with and without the card installed while the computer was idle for at least 10 minutes. The difference between the two readings is 13 watts. This controller utilizes the Intel IOP348 I/O processor which requires a little more power than most other SATA host adapters.
RAID Types
The Areca ARC-1680x provides many RAID functions that Macintosh users may not be familiar with. While RAID 0 and RAID 1 functions are provided in Disk Utility, the ARC-1680x can provide many additional RAID types.
RAID 3 - disk striping and complete data redundancy provided by a dedicated parity drive. RAID 3 breaks up data into smaller blocks, calculates parity by performing an exclusive-or on the blocks, and then writes the blocks to all but one drive in the array. The parity data created during the exclusive-or is then written to the last drive in the array. If only a single drive fails, the data should be recoverable.
RAID 5 - stripes data at the block level across several hard drives while distributing parity among these drives. If a single hard drive fails, RAID 5 can usually recover using the rebuild features. If more than one drive fails the data on the RAID is lost. This system provides redundancy with the least amount of hard drives. Backup of data is still necessary with RAID 5, but this array provides some crash protection while a striped RAID set provides none.
RAID 6 - stripes data at the block level across several hard drives. Next a dual set of parity data is calculated and distributed across all of the drives. RAID 6 is similar to RAID 5, but it performs dual parity computations. Up to two hard drives can fail simultaneously and RAID 6 can usually still rebuild the volume. RAID 6 provides a high level of redundancy. However, if more than two drives fail, data on the RAID will be lost.RAID 10 - creates a striped RAID set with half of the hard drives and a mirror of each hard drive is created so that an exact duplicate of the striped RAID set is available. This configuration can still operate at full speed with a hard disk failure. Unmounting a failed hard drive and inserting another hard drive of the same capacity or larger will allow the RAID 10 to rebuild. Any single disk can fail and no data will be lost as long as the mirror or the original disk is functional. Backup of critical files is still prudent but the redundancy of a RAID 10 disk array is very good. The Areca RAID 10 implementation offers advanced flexibility as the number of disks in the array can be even or odd.
RAID 30 - is a combination of multiple RAID 3 volumes striped in a RAID 0 configuration. Two or more volumes are required to create a RAID 30 disk array. Up to one hard disk in each RAID 3 set can fail and the volume can still usually be rebuilt.
RAID 50 - is a combination of multiple RAID 5 volumes striped in a RAID 0 configuration. Two or more volumes are required to create a RAID 50 disk array. Up to one hard disk in each RAID 5 set can fail and the volume can still usually be rebuilt.
RAID 60 - is a combination of multiple RAID 6 volumes striped in a RAID 0 configuration. Two or more volumes are required to create a RAID 60 disk array. Up to two hard disks in each RAID 6 set can fail and the volume can still usually be rebuilt.
PerformanceThe Areca ARC-1680x was tested while installed in slot 4 of an Apple Mac Pro running Mac OS X 10.4.10. Eight 320GB Seagate 7200.10 hard drives were used to create various RAID configurations while mounted inside the EnhanceBox E8-ML. DiskTester 2.0 10GB read and write tests were performed using a run area test so that this article could display how the RAID performed. DiskTester is a Terminal application that measures the combined performance of a volume and the Mac OS X operating system. Using the command: ./disktester run-area-test --chunk-size 128M --test-size 10G --delta-percent 10 DriveName, puts DiskTester to work testing how the RAID will perform when empty, 10% full, 20% full and so on. The table below displays how the ARC-1680x performed when using RAID 5 and RAID 6 configurations.
Areca ARC-1680x - Eight Drive RAID 5 & 6 Comparison
| Area Full | write | read | write | read | write | read | write | read |
| empty | 452 | 490 | 419 | 422 | 392 | 421 | 358 | 353 |
| 10% | 455 | 484 | 434 | 417 | 392 | 415 | 347 | 345 |
| 20% | 454 | 482 | 429 | 411 | 386 | 412 | 352 | 342 |
| 30% | 454 | 469 | 416 | 402 | 391 | 402 | 350 | 334 |
| 40% | 454 | 452 | 402 | 385 | 396 | 386 | 336 | 322 |
| 50% | 450 | 428 | 386 | 367 | 380 | 367 | 321 | 306 |
| 60% | 419 | 399 | 357 | 343 | 358 | 342 | 298 | 287 |
| 70% | 395 | 378 | 337 | 323 | 337 | 324 | 282 | 270 |
| 80% | 357 | 341 | 304 | 292 | 304 | 292 | 253 | 243 |
| 90% | 316 | 303 | 270 | 260 | 270 | 260 | 222 | 217 |
| 100% | 260 | 249 | 222 | 213 | 222 | 213 | 180 | 180 |
| Average | 406 | 407 | 362 | 349 | 348 | 349 | 300 | 291 |
| Format Size | 2.04TB | 1.75TB | 1.75TB | 1.45TB | ||||
| Hot Spare | No | Yes | No | Yes | ||||
| Redundancy | Yes | Yes | Yes | Yes |
The performance results above indicate that an ARC-1680x using an eight drive Seagate 320GB 7200.10 in a RAID 5 configuration with the EnhanceBox E8-ML and an Apple Mac Pro can provide average read and write performance of over 400MB/sec. Using seven hard drives to configure the RAID 5 with a hot spare reduces the average write performance to 362MB/sec. and the average read performance to 349MB/sec. This setup reduces performance by the speed of one disk drive but provides the ability to automatically rebuild the RAID 5 volume if a single hard drive fails.The ARC-1680x RAID 6 configuration is able to provide performance that is close to the RAID 5 setup with a hot spare. This is pretty amazing as RAID 6 is required to calculate an additional set of parity data and distribute it across all of the hard drives. The 800MHz Intel IOP348 I/O processor mounted on the ARC-1680x makes this possible.
While RAID 6 provides twice the redundancy of RAID 5, some users may want to consider using an ARC-1680x RAID 6 configuration with a hot spare. This allows the RAID 6 to rebuild automatically in the case of a hard drive failure. Servers that are difficult to get to or off site may be possible candidates for hot spare usage. Hot spares setup with the ARC-1680x do not spin up until they are needed. This feature helps keep the spare from experiencing extra wear while waiting to be used.
RAID 6 Redundancy
During this review, the RAID 6 rebuild capability of the ARC-1680x was tested. Initializing the RAID 6 volume required 6 hours and 2 minutes using eight Seagate 320GB hard drives. Larger hard drives will require additional time. Once the RAID 6 volume was created, a single hard drive was pulled to simulate a disk failure. The Areca web interface indicated that the RAID set was "Degraded" and displayed which hard drive had failed. The RAID 6 volume was still 1.75TB in size and fully usable. DiskTester was run to determine how performance might be impacted with a failed hard drive. The write performance of the degraded RAID 6 volume was not materially impacted by the hard drive failure. However, average read performance dropped from 349MB/sec to 191MB/sec.
Next, a second hard drive was removed from the RAID 6 volume to simulate a second hard drive failure. The RAID was still very usable. Once again write performance was minimally impacted. This time the average read performance actually rose a little to 213MB/sec. When two replacement hard drives were inserted the Areca ARC-1680x automatically started rebuilding the RAID 6 volume. The table below displays the DiskTester performance results of the original initialized RAID 6 volume and each step of the failure test plus the automatic rebuilding period.
Areca ARC-1680x - RAID 6 Drive Failure Performance Test
| Area Full | write | read | write | read | write | read | write | read |
| empty | 392 | 421 | 433 | 203 | 438 | 223 | 344 | 363 |
| 10% | 392 | 415 | 430 | 205 | 441 | 225 | 434 | 200 |
| 20% | 386 | 412 | 428 | 198 | 426 | 228 | 429 | 201 |
| 30% | 391 | 402 | 418 | 197 | 419 | 228 | 415 | 198 |
| 40% | 396 | 386 | 404 | 198 | 400 | 220 | 404 | 189 |
| 50% | 380 | 367 | 386 | 191 | 386 | 220 | 386 | 183 |
| 60% | 358 | 342 | 360 | 189 | 360 | 215 | 355 | 184 |
| 70% | 337 | 324 | 337 | 191 | 338 | 209 | 335 | 177 |
| 80% | 304 | 292 | 304 | 185 | 304 | 204 | 300 | 171 |
| 90% | 270 | 260 | 270 | 181 | 269 | 194 | 268 | 154 |
| 100% | 222 | 213 | 220 | 164 | 222 | 176 | 218 | 138 |
| Average | 348 | 349 | 363 | 191 | 364 | 213 | 354 | 196 |
| Format Size | 1.75TB | 1.75TB | 1.75TB | 1.75TB | ||||
| Hot Spare | No | No | No | No | ||||
| Redundancy | Yes | Yes | No | Yes |
The Areca ARC-1680x RAID 6 controller provides amazing stability. Pulling two hard drives from the RAID 6 volume did not significantly reduce its write performance. The read performance was reduced by approximately 40% but the array still provided average read performance over 190MB/sec. During the rebuilding process the RAID 6 volume was still able to provide an average of 354MB/sec. write performance and 196MB/sec. read performance. The rebuilding process slows if the RAID volume is being accessed and resumes at full speed once the volume is available. Rebuilding the RAID 6 volume with two new hard drives required 3 hours and 26 minutes. Once the RAID 6 was fully rebuilt it was able to perform at full speed with no loss of data. While users should always have a backup of important data, the redundancy provided by the ARC-1680x RAID 6 controller is reliable and easy to use.
RAID 0 & 3
RAID users looking for high speed will find that RAID 0 is the top performer. While RAID 0 provides zero redundancy, it delivers the fastest performance. Using the same eight Seagate 320GB 7200.10 hard drives, the Areca ARC-1680x configured in RAID 0 mode with the web interface was able to provide an average write speed of over 467MB/sec. and an average read speed of 466MB/sec.
Areca ARC-1680x - Eight Drive RAID 0 & 3 Comparison
| Area Full | write | read | write | read | write | read | write | read |
| empty | 523 | 565 | 507 | 494 | 439 | 495 | 411 | 421 |
| 10% | 525 | 559 | 511 | 491 | 442 | 484 | 414 | 423 |
| 20% | 524 | 548 | 512 | 492 | 444 | 483 | 412 | 411 |
| 30% | 520 | 534 | 512 | 482 | 444 | 470 | 418 | 401 |
| 40% | 524 | 518 | 508 | 466 | 449 | 449 | 403 | 385 |
| 50% | 517 | 493 | 511 | 447 | 449 | 429 | 386 | 367 |
| 60% | 480 | 457 | 480 | 403 | 420 | 399 | 359 | 344 |
| 70% | 454 | 430 | 454 | 378 | 395 | 375 | 340 | 324 |
| 80% | 409 | 392 | 409 | 362 | 357 | 341 | 305 | 292 |
| 90% | 362 | 347 | 361 | 333 | 313 | 303 | 270 | 260 |
| 100% | 298 | 285 | 297 | 285 | 260 | 249 | 222 | 213 |
| Average | 467 | 466 | 460 | 421 | 401 | 407 | 358 | 349 |
| Format Size | 2.33TB | 2.33TB | 2.04TB | 1.75TB | ||||
| Hot Spare | No | No | No | Yes | ||||
| Redundancy | No | No | Yes | Yes |
When the ARC-1680x was configured in JBOD mode and Disk Utility was used to setup the RAID 0, the read speed of the RAID was reduced by approximately 10% on average. Based on this information, users will want to keep the ARC-1680x configured in RAID mode for increased performance results.
The Areca ARC-1680x also supports RAID 3 configurations. RAID 3 provides high performance for transfer rate intensive applications and can recover from the failure of a single hard drive. According to these tests a RAID 3 configuration provides DiskTester results that are very similar to RAID 5.
RAID 10, 30, 50, 60
The Areca ARC-1680x supports RAID 10 with a special feature. An even number of hard drives is not required. This option allows the ARC-1680x to support a RAID 10 configuration with a hot spare while using only eight hard drives. This feature allows the user to configure a hot spare with a RAID 10 volume without reducing the RAID size to an even number of disks.
The Areca ARC-1680x also allows users to create RAID 30, 50 and 60 disk arrays. This configuration requires the use of multiple RAID volumes. When the "Create 30/50/60" menu is selected, the volumes are configured as RAID 3, 5 or 6 and striped in a RAID 0 configuration. This process creates the new RAID 30, 50 or 60 array. These formats can provide additional redundancy with large disk arrays.
Areca ARC-1680x - RAID 10, 30, 50, 60 Performance
| Area Full | write | read | write | read | write | read | write | read |
| empty | 259 | 284 | 377 | 426 | 390 | 421 | 261 | 283 |
| 10% | 262 | 280 | 384 | 413 | 392 | 419 | 264 | 278 |
| 20% | 263 | 276 | 382 | 411 | 391 | 410 | 264 | 274 |
| 30% | 263 | 270 | 377 | 401 | 388 | 401 | 264 | 269 |
| 40% | 263 | 259 | 381 | 389 | 388 | 391 | 264 | 259 |
| 50% | 256 | 246 | 384 | 368 | 384 | 367 | 256 | 244 |
| 60% | 240 | 230 | 357 | 342 | 344 | 344 | 239 | 230 |
| 70% | 226 | 218 | 340 | 323 | 338 | 323 | 226 | 217 |
| 80% | 203 | 194 | 304 | 292 | 306 | 293 | 203 | 194 |
| 90% | 181 | 174 | 270 | 260 | 270 | 260 | 181 | 174 |
| 100% | 148 | 143 | 221 | 213 | 222 | 214 | 148 | 143 |
| Average | 233 | 234 | 343 | 349 | 347 | 349 | 234 | 233 |