Fibre Channel SAN — 30 Frequently Asked Questions
Real questions enterprise IT engineers ask about Fibre Channel SAN, with practical answers from Pro Disk Engineering. Questions sourced from Server Fault and Network Engineering Stack Exchange under CC BY-SA — see source links per question. Answers are original Pro Disk Network content with links to our buying guides and product catalog.
What is the difference between SAN, NAS and DAS?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (79 votes · 159,159 views) ›
LV Status: Not available. How to make it available?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (36 votes · 103,407 views) ›
Howto show connected targets in Linux?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (18 votes · 103,064 views) ›
Testing whether jumbo frames are actually working
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (33 votes · 58,894 views) ›
Best practice for assigning private IP ranges?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (19 votes · 86,086 views) ›
Fibre channel long distance woes
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
RAID level guidance: for HDD arrays of drives 4 TB or larger, use RAID 6 (dual parity). RAID 5 is no longer responsible at large drive sizes — the rebuild window exceeds typical MTBF. RAID 10 (stripe of mirrors) wins for OLTP databases and VDI write caches.
Transceiver selection: DAC for 1-7m, AOC for 7-30m, SR optics on MMF up to 100m, LR optics on SMF up to 10km. Vendor coding matters — Cisco-coded optics avoid "service unsupported-transceiver" warnings on IOS / NX-OS.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (52 votes · 2,083 views) ›
What is a Storage Area Network, and which benefits does it have over different storage solutions?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (37 votes · 8,305 views) ›
Pay no attention to that SAN behind the curtain
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
RAID level guidance: for HDD arrays of drives 4 TB or larger, use RAID 6 (dual parity). RAID 5 is no longer responsible at large drive sizes — the rebuild window exceeds typical MTBF. RAID 10 (stripe of mirrors) wins for OLTP databases and VDI write caches.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (38 votes · 1,759 views) ›
What kind of storage do people actually use for VMware ESX servers?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (27 votes · 17,094 views) ›
How should I set up my Fibre Channel (FC) network?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (27 votes · 16,435 views) ›
Cheapest iSCSI SAN for Windows 2008/SQL Server clustering?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
BMC access: ipmitool -H <ip> -U admin -P <pw> chassis status for remote IPMI. For Dell iDRAC, HPE iLO, Lenovo IMM/XCC, Supermicro IPMI — all expose Redfish REST API as the modern alternative.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (25 votes · 20,064 views) ›
Tuning iSCSI storage
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (29 votes · 12,031 views) ›
Fibre Channel LUN rescan and QLogic
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (9 votes · 46,839 views) ›
SQL Server disk design on an ISCSI SAN
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (27 votes · 9,327 views) ›
Incredibly slow snapshot removal
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (15 votes · 25,858 views) ›
SQL Server Files Local or NAS or SAN?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
RAID level guidance: for HDD arrays of drives 4 TB or larger, use RAID 6 (dual parity). RAID 5 is no longer responsible at large drive sizes — the rebuild window exceeds typical MTBF. RAID 10 (stripe of mirrors) wins for OLTP databases and VDI write caches.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (15 votes · 20,474 views) ›
Checking fiber cables for light without risking my eyes
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (22 votes · 5,240 views) ›
Why would a heavily disk intensive application run faster on a SAN than on a Physical Disk?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
Disk I/O observability: iostat -xz 5 for per-device throughput, iotop for per-process I/O attribution, dstat for combined dashboards. For long-term capture, push node_exporter output to Prometheus.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (21 votes · 2,658 views) ›
iSCSI, multiple initiators for the same LUN
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (12 votes · 18,886 views) ›
How to crack the 1 Gbit iSCSI limit between ESXi and VNXe
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
RAID level guidance: for HDD arrays of drives 4 TB or larger, use RAID 6 (dual parity). RAID 5 is no longer responsible at large drive sizes — the rebuild window exceeds typical MTBF. RAID 10 (stripe of mirrors) wins for OLTP databases and VDI write caches.
Interface selection: NVMe (PCIe Gen4/5) for random workloads above 500 IOPS. SAS SSDs for mid-tier. SATA HDDs for capacity / backup tiers. Match drive interface to RAID controller; mismatches force fallback to lowest common denominator.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (15 votes · 7,528 views) ›
Linux goes to swap while plenty of RAM installed
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
Interface selection: NVMe (PCIe Gen4/5) for random workloads above 500 IOPS. SAS SSDs for mid-tier. SATA HDDs for capacity / backup tiers. Match drive interface to RAID controller; mismatches force fallback to lowest common denominator.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Linux memory accounting: RSS = physical RAM in use, VIRT = virtual address space (includes mapped files), PSS = proportional shared pages. The "available" column in free already accounts for reclaimable cache — use that as your real free-RAM number.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (14 votes · 7,066 views) ›
Can you connect a SAN directly to a HBA with Fibre Channel?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (10 votes · 11,931 views) ›
IQN Naming convention
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (11 votes · 9,127 views) ›
Poor iSCSI performance with SSD disks and 10 Gbe network
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
RAID level guidance: for HDD arrays of drives 4 TB or larger, use RAID 6 (dual parity). RAID 5 is no longer responsible at large drive sizes — the rebuild window exceeds typical MTBF. RAID 10 (stripe of mirrors) wins for OLTP databases and VDI write caches.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (10 votes · 8,389 views) ›
How to utilize spare workstation drive space for server storage/backup
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
Interface selection: NVMe (PCIe Gen4/5) for random workloads above 500 IOPS. SAS SSDs for mid-tier. SATA HDDs for capacity / backup tiers. Match drive interface to RAID controller; mismatches force fallback to lowest common denominator.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (11 votes · 1,457 views) ›
Cheap but Highly Available Shared Storage?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Correct placement of devices on a Fibre Channel fabric
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Original question on Server Fault (10 votes · 1,051 views) ›
How Fibre Channel Frames are populated and traverse a Fabric?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
FCoE, on any Ethernet switch?
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
The answer depends on your specific platform, workload, and operational requirements. For environment-specific guidance, email sales@prodisknetwork.com with your server model and target configuration.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
Can I dynamically expose an entire SCSI host over Fibre Channel, preferably in Linux
Fibre Channel SAN questions usually involve speed selection, HBA interop, or zoning discipline.
iSCSI / FC LUN scanning: from Linux iscsiadm -m discovery + iscsiadm -m node --login; on Windows, refresh in iSCSI Initiator. Rescan SCSI bus with echo "- - -" > /sys/class/scsi_host/hostN/scan.
Pro Disk Network ships Emulex / QLogic HBAs and Brocade / Cisco MDS switches. FC buying guide · SAN catalog
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