iSCSI for TL-Series Tape Libraries
SEPTEMBER 2008
SECTION 1
EXECUTIVE SUMMARY
To supplement the growth in iSCSI SANs, Dell has introduced an iSCSI-to-SAS bridge card
for the TL-series of tape libraries (Dell PowerVault TL2000 & TL4000). This offering allows a
customer to directly attach a tape backup target to their iSCSI 1Gb Ethernet SAN with little to
no degradation in transfer speed, 90 MB/s in most cases. The following white paper explores
the setup, configuration and considerations associated with implementing this solution.
SECTION 2
INTRODUCTION
This white paper assumes a typical SMB environment with 5-10 Windows servers as an exam-
ple of how to implement an iSCSI tape backup solution. The example SMB network incorpo-
rates an iSCSI 1GbE SAN containing disk (primary/secondary storage) and tape (backup &
archive) elements. The intent is to provide insight into the purchase decisions and setup con-
siderations regarding the ISVs, server initiators, networks and storage target. Please note,
there are many different variations – this is just one of them. The primary focus will center
around the set up and configuration of an iSCSI network and perform back-ups to it.
In our example network, at least one server will need to be attached to the backup elements.
Depending on your backup window constraints and availability of existing servers during that
time, one of those might even be used. In general, the smaller the backup window, the greater
the number of servers that are required to be connected to the backup elements. In the exam-
ple here, the assumption is there are no backup window constraints (can backup overnight)
and there is one server available (and necessary) to be connected to the disk and tape device.
Server
TL2000/TL4000
TL24iSCSIxSAS
Now that the example network topology has been defined, let's explore the benefits of an
iSCSI SAN as compared to alternatives.
Why might you choose iSCSI?
Cost – iSCSI networks typically cost less to acquire and maintain than the equivalent Fibre
Channel version
Ease of Installation – iSCSI networks only require the same basic networking skills used in
maintaining a standard IP network (cf., Fibre Channel)
Scalability – One of the advantages over direct attach is the ability for ready expansion as
business needs grow.
Server
Server
Back-up Server
MD3000i
with
Server
LAN
iSCSI SAN
4
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