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My thoughts so far on IP-SAN vs Fibre SAN
I’ve been doing a bit of research on iSCSI and Fibre SAN and here’s what I’ve found.
The King Fibre Channel SAN:
1. Speed- 4Gb is the new champion 2Gb will be the entry level.
2. Network Congestion- Since the storage is centrally located behind Fibre Switch net congestion is minimized. Server to server copies happen really fast.
3. Long Fibre cable runs.
4. Reliable proven techThe downsides
Fibre Switch costs
Fibre HBA costs
Somewhat restricted placement
Need for a RAID ArrayiSCSI …potentially potent new challenger
1. Speed- Line speed which typically means GIGe but many people forget you could aggregate 4 GIGe ports at the switch for 4Gb connections. In a few years 10G will be feasible. iSCSI will have nice scalability here
2. Cost- No need for HBA unless you have a high IOP task like running an Exchange Server or DB. Freely downloadable iSCSI initiators will “trick” computer into thinking local Ethernet NIC is SCSI card.
3. Utilizes existing network infrastructure. Lower startup costs.
4. iSCSI boot. IBM booted a computer in Tel Aviv from a iSCSI Target in Seattle WA. Imagine the ease of management when you’re booting “diskless” Servers over the network.Downsides
Performance is limited to line speed
Network Congestion must be dealt with
iSCSI commands can overwhelm Server in some cases HBA helps here.
Not as proven as FC SAN but vendor support is rapidly rising.Coolest stuff I’ve seen so far.
iSCSI accelerator that doesn’t kill ethernet functionality
Alacritech has the right product mix in the SES200. You get TCP Offload for iSCSI acceleration and you keep ethernet features like the Port Trunking 802.3ad aggregation. It’s the only card I know that does this until cards start using the Broadcom BCM8708S chip which has iSCSI, TOE and RDMA on one chip.
Ethernet inventor says Fibre Channel Doomed
He’s probably right. With 10G ethernet available now but very expensive, ethernet’s ubiquidity will be hard to beat.