Adaptec AHA-3985 Quick guide

Benchmark Report
Fault-Tolerant Configurations
AHA-3985 PCI RAID Adapter
vs.
NetWare

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Table of Contents
Table of Contents
Abstract....................................................................................................................1
Introduction..............................................................................................................1
RAID Levels............................................................................................................1
Benchmark Description............................................................................................1
Performance..............................................................................................1
Reconstruction Time.................................................................................2
Results......................................................................................................................3
Performance..............................................................................................3
Reconstruction Time.................................................................................4
Conclusion ...............................................................................................................5
Trademarks
AHA is a trademark of Adaptec, Inc.
Novell and NetWare are trademarks of Novell, Inc.
NetBench is a trademark of Ziff Davis Publishing Company

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Page 1
Abstract
This report summarizes the results of a performance comparison between Novell NetWare’s®
embedded volume mirroring configuration and Adaptec’s AHA-3985 PCI RAID adapter. The
AHA-3985 provides performance and recovery time improvements through advanced fault-
tolerance functionality in a typical NetWare installation as measured by Ziff-Davis’
NetBench®version 3.01.
Introduction
In today’s information intensive decision making process, information accuracy and
accessibility is essential. The failure of a file server, even temporarily, can critically impede
the successful operations of an organization. The solution to the availability problem is RAID
(Redundant Array of Inexpensive Disks). RAID employs a data redundancy scheme, so that
in the event of a hard disk failure, there is no interruption in data accessibility and no
information is lost. While the benefits of redundantly storing data is readily apparent in the
presence of a failure, system performance and flexibility during non-critical times must also
be considered when selecting a storage subsystem.
RAID Levels
Within every installation of NetWare, LAN administrators have the option of mirroring data
partitions such that in the event a drive fails, there is a complete copy of the data already
online. This is commonly known as RAID level 1 or mirroring. Adaptec’s AHA-3985 PCI
RAID adapter fully supports RAID level 1 as well as the more advanced RAID level 5. RAID
5 is the striping of data across an array of drives with redundancy parity data spread across all
drives. It is this parity data that allows the system to reconstruct the data of a down drive
using only the data on the remaining drives. Because the data is striped across a number of
drives, total I/O throughput is improved, giving RAID 5 superior I/O performance.
Benchmark Description
Performance
To measure the performance levels of the different configurations, Ziff-Davis’ NetBench®
version 3.01 was set up using 20 client machines. The clients were arranged in 4 groups of 5
and connected to the server through a quad-port Ethernet adapter. (A complete listing of
hardware and software used in this benchmark report can be found in Appendix A.) From
NetBench, the Disk Mix test was selected as being representative of a real world situation.
The user’s manual describes Disk Mix as ...
A NetBench 3.01 test that provides you with the primary measure of your
server’s file I/O performance. The Disk Mix runs a series of tests based on
information gained from profiling actual applications. As a result, the Disk
Mix exercises your file server the way real users do, but much more
intensely.....

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Page 2
The Disk Mix mirrors the way leading PC applications perform network file
operations. Based on information gained by profiling leading DOS
applications, the Disk Mix uses different block sizes and different operations
during the test to place a diverse load on the server. It opens and closes files,
creates and deletes them, reads and writes file data, intersperses read
and write operations, and traverses directories. The files include data from
both text and binary file types. In addition, the Disk Mix uses both shared
and private server directories and files to simulate both shared file access
and private file access.
To compare the I/O performance of NetWare’s native mirroring feature and the AHA-3985’s
RAID configurations, the Disk Mix test was run on an array of drives and the total I/O rate in
kilobytes per second was recorded. For the native NetWare mirroring configuration, an
Adaptec AHA-2940 was used as the SCSI interface adapter.It is important to note that the
Disk Mix test intensely exercises the file server, such that a load of 20 clients is
equivalent to 40 - 100 average users, depending on the definition of average user.
Reconstruction Time
After a device failure, the system administrator typically replaces the failed unit with a new
or spare unit. The system then reconfigures the new unit with data to bring the array back to
full fault-tolerant condition. During this time, the data volume is vulnerable to another device
failure. Therefore minimizing the reconstruction time, reduces the data’s exposure to loss and
server down time. This benchmark records the time required for NetWare to reconstruct a
mirrored drive and compares it to the time the AHA-3985 needs to reconstruct a mirrored
drive and a RAID 5 array.

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Page 3
Results
Performance
Figure 1 below graphs the results of the Disk Mix test for the different configurations in
kilobytes per second. The AHA-3985 provides I/O performance improvements during normal
operations in both RAID 1 and RAID 5 configurations of 19% and 28%, respectively. This
translates into better system performance seen by end users when accessing a data volume
controlled by the AHA-3985.
AHA-3985
RAID 5 AHA-3985 Mirror NetWare Mirror
0
200
400
600
800
1000
1200
1400
1600
1800
KBytes/Sec
AHA-3985
RAID 5 AHA-3985 Mirror NetWare Mirror
Fault Tolerant Performance
3 HDDs
2 HDDs
2 HDDs
Figure 1

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Page 4
Reconstruction Time
Figure 2 displays the time required for the system to reconstruct a new drive and return the
system to full fault-tolerance status. The AHA-3985 and its software drivers are able to
significantly shorten the reconstruction time by 60% and 40% over NetWare mirroring for
RAID 1 and RAID 5 respectively. This improvement in reconstruction time allows the
system to return to full fault-tolerant status more quickly, thus reducing the chances of data
loss from a second hardware failure.
AHA-3985
RAID 5 AHA-3985 Mirror NetWare Mirror
0
5
10
15
20
25
30
35
40
Minutes
AHA-3985
RAID 5 AHA-3985 Mirror NetWare Mirror
Reconstruct Completion Time
Figure 2

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Page 5
Conclusion
Clearly with the increasing reliance on LAN servers, availability to all data at any time has
become a fundamental requirement in today’s business environment. Within an entry level
NetWare installation, system administrators have basically only had the option of mirroring
data volumes using NetWare’s native operating system support. The AHA-3985 PCI RAID
adapter improves data I/O performance in mirroring configurations and provides the
additional feature of RAID 5 for more flexible and cost effective data redundancy. In a
typical NetWare configuration, the AHA-3985 is able to perform up to 28% faster than
NetWare’s native fault-tolerant mode of operation. The AHA-3985 restores a mirrored drive
to fault-tolerant status 60% faster than NetWare, thus reducing the exposure to data loss.
Overall, the AHA-3985 provides system administrators with better performance, increased
flexibility and more advanced features, such as hot spare support, than traditional NetWare
mirroring, while minimizing the possibility of data loss due to additional devices failures.

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Appendix A
Appendix A
File Server Specifications
File Server: Intel Plato Motherboard, BIOS 0.01.20.AX1
Processor Type: Intel Pentium
Number of Processors: 1
Processor Speed: 90 MHz
Clock Speed: 90 MHz
System RAM: 32 MB
Secondary RAM Cache: 256 KB
Hardware Hard Disk Cache: N/A
Number of Hard Disk Controllers: 1
Type of Hard Disk Controllers: Adaptec AHA-3985 (AHA-2940)
1
Type of I/O Bus: PCI
Number of Hard Disks: 3 (2)
Type of Hard Disks: Seagate ST32550N F/W - 0014
Hard Disk Sizes: 2 GB
Controller Driver Version: AHA3980.DSK/ARDRVR.DSK - 1.01
(AIC7870.DSK - 1.20)
Disk Organization: RAID 5 (Mirror)
Boot Channel Drive Controller: AHA-1542, ISA
System Boot Drive: Maxtor MXT-540S
Number of Network Controllers: 1
Network Interface: Cogent eMaster+ PCI Quartet
Network Interface Driver: EM964_4.LAN - Ver 1.10
Network Operating System: Novell Netware
Operating System Version: 3.12
Network Operating System
Parameters: Disk Read After Write = Off
Immediate Purge of Deleted Files = On
Enable IPX Checksums = 1
1( ) Indicates used for mirroring configurations.

ECX Applications Engineering January 3, 1996
Adaptec, Inc. Appendix A
Client Specifications
Network Type: 10Base-T, Ethernet
Number of Clients: 20
Number of Concentrators: 4
Type of Concentrators: Accton Etherhub-8mini
Number of Clients per Segment: 5
Network Interface Card: NE2000
Client CPU type: Intel 486
Client CPU Speed: 33 MHz
Client Network Software: MSDOS 6.0, IPX/SPX 3.10, NetX 3.32
Size of Client Network Cache: N/A
Controller Specifications
Controller Operating System: MSDOS 6.22, Windows for Workgroups 3.11
Network Software: LSL 2.14, NE2000 2.02, IPX/SPX 3.01, VLM 1.20