Last year, Tweakers.net put a lot of energy in the development of an extensive and representative set of server benchmarks. Several server applications were simulated on a dual Opteron 244 running Windows Server 2003 (Intel IPEAK SPT only runs on Windows sytems). The server was equipped with 8GB of memory and a SCSI RAID setup configured with two 10K hard drives and six 15K hard drives. The ultimate goal was to trace disk access patterns from various server scenarios. The server StorageMark 2004 Index consists of traces from disk-to-disk backup servers, file servers, database servers, streaming media servers and mail servers. Further information is found on this page (Dutch only).
The characteristics of the differenty types of server applications vary greatly and therefore it is debetable if it makes sense to summarise server performance within just a single digit. For this reason, the results of the high concurrency scenarios will be discussed individually. The heavy tests are representative for the typical use of large RAID arrays. People who prefer a simplified comparison can make their choice based on the performance in the server index. Products exhibiting good performance in the Server StorageMark 2004 Index generally won't be terrible products, at least performance wise. Obviously we have skipped benchmarks of the RAID 0 performance in the server workloads. RAID 0 wil only be used in users 'by accident'.
The first graph produces an excellent picture for the Areca ARC-1120, which performs admirably in RAID 10. The RAID 1 performance of the Areca board is at the same level as the 3ware Escalade 8506-8 and the Promise FastTrak S150 SX4, and a bit behind the LSI MegaRAID SATA 150-4/6. With respect to RAID 1 performance, the 3ware Escalade 9500S-8, HighPoint RocketRAID 1820A and RAIDCore BC4852 fall somewhat behind the first group of contenders, but the differences between the controllers are not that big. This also applies to the RAID 10 performances of all boards except the Areca ARC-1120.
In RAID 5, the Areca ARC-1120 generally offers the highest server performance. The RAIDCore BC4852 also provides good results. The midfield is occupied by the LSI MegaRAID SATA 150-4/6 and the HighPoint RocketRAID 1820A. In RAID 5 configurations consisting of three and four drives, the LSI Logic and HighPoitn adapters performance nearly identical to the RAIDCore BC4852. With six and eight disks, performances does not improve a lot, however. The products manufactured by 3ware and Promise occupy similar disappointing positions as seen previously seen in the RAID 5 desktop benchmarks. The Escalade 8506-8 fails to improve over the performance of a single disk while the Escalade 9500S-8 is only slightly faster than one Raptor WD740GD.
A selection of the tests from the server suite will be discusses individually on the next pages. The stripe size used by the adapters was tweaked for optimal performance in the server index, and therefore was not optimized for each individual test. It would be too time consuming to run the tests with all possible stripe size settings for each RAID level. In some cases, multiple tests for a certain RAID configuration were run (to examine which stripe size or cache setting wouold deliver the best performance in the server index). In that case we will display the best result for the invidual tests. This could be result which set at a different setting than the configuration delivering the highest index score.
The first test is a scenario simulating a high concurrency disk-to-disk backup server. The use of disk arrays for backup storage is increasing day by day. Disk storage is frequently combined with tape storage to create tiered storage systems: first data is written to a backup array and at a later time the backup is copied to tape. The advantage is a smaller backup window, lower loads on the backup clients, and faster data transfer to tape drives. Because of their low price per gigabyte, Serial ATA hard drives are ideally suited for use in backup servers. Coupled with a high performance RAID adapter, Serial ATA hard drives can offer high performance and excellent reliability.
The high concurrency version of the backup server simulation is a scenario in which seven clients are writing backup data to the server using two gigabit ethernet connections. During the trace, the simulation server reached network transfer rates of 70MB/s. A total amount of 43GB of data was written to the backup server. The performance of the write-back cache has a large effect on performance, as well as the capacity to handle large I/O queues. On average 30 I/Os where waiting to be processed by the RAID adapter.
The results of the RAID 1 and RAID 10 benchmarks place the Areca ARC-1120 once again in the first spot. The 3ware Escalade 9500S-8 delivers a disappointing performance. We have seen better RAID 1 and RAID 10 results from this adapter. The LSI MegaRAID SATA 150-4/6 does a nice job in RAID 1 and the 3ware Escalade 8506-8 is performing quite good in RAID 10 as well.
The RAID 5 graph shows excellent results from the MegaRAID in configurations with three and four disks. Unfortunately, the performance of the MegaRAID doesn't scale beyond four drives. The Areca ARC-1120 and the RAIDCore BC4852 offer good performance in all disk configurations. Starting at six drives, these adapters provide significantly better performance than a single Raptor. The two 3ware cards offer very disappointing RAID 5 performance. In all RAID 5 configurations they perform worse than a single disk.