DRBD (Distributed Replicated Block Device) a low cost HA solution (alternate to SRDF)

Some of the key features

  • DRBD® refers to block devices designed as a building block to form high availability (HA) clusters. This is done by mirroring a whole block device via an assigned network. DRBD can be understood as network based raid-1
  •     DRBD® available under the terms of The GNU General Public License v2
  • Fully synchronous, memory synchronous or asynchronous modes of operation




How to check if Linux has Fibre card installed or not?

How to check if Linux box has f Fibre card installed or not…. Below are few methods that, you can tell end user if underline Linux server has Fibre card installed.

# lspci | grep -i emulex
0b:00.0 Fibre Channel: Emulex Corporation Zephyr-X LightPulse Fibre Channel Host Adapter (rev 02)

<<<< For more details like the speed card is operating etc >>>>

# lspci -vv | less
Fibre Channel: Emulex Corporation Zephyr-X LightPulse Fibre Channel Host Adapter (rev 02)
Subsystem: Emulex Corporation Zephyr-X LightPulse Fibre Channel Host Adapter
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR- FastB2B-

Status: Cap+ 66Mhz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- SERR- Latency: 0, Cache Line Size 10
Interrupt: pin A routed to IRQ 217
Region 0: Memory at f9ff0000 (64-bit, non-prefetchable) [size=4K]
Region 2: Memory at f9fe0000 (64-bit, non-prefetchable) [size=256]
Region 4: I/O ports at 4000 [size=256]
Capabilities: [58] Power Management version 2
Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [60] Message Signalled Interrupts: 64bit+ Queue=0/4 Enable-
Address: 0000000000000000 Data: 0000
Capabilities: [44] Express Endpoint IRQ 0
Device: Supported: MaxPayload 2048 bytes, PhantFunc 0, ExtTag+
Device: Latency L0s <4us, L1 <16us
Device: AtnBtn- AtnInd- PwrInd-
Device: Errors: Correctable- Non-Fatal+ Fatal+ Unsupported-
Device: RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
Device: MaxPayload 512 bytes, MaxReadReq 4096 bytes
Link: Supported Speed 2.5Gb/s, Width x4, ASPM L0s, Port 0
Link: Latency L0s <4us, L1 unlimited
Link: ASPM Disabled RCB 64 bytes CommClk- ExtSynch-
Link: Speed 2.5Gb/s, Width x4
Capabilities: [100] Advanced Error Reporting
Capabilities: [12c] Power Budgeting

<<<< You can check if required driver is installed or not >>>>

# dmesg | grep -i emulex
Emulex LightPulse Fibre Channel SCSI driver
Copyright(c) 2003-2007 Emulex. All rights reserved.

Another way to check this out is check for /proc/scsi

Fibre channel is visible in the /proc/scsi hierarchy, but the exact path depends on the manufacturer (Emulex, Qlogic) of the Fibre Channel adapter + device driver. in my case it is as below –

# ls -l /proc/scsi/lpfc/0
-rw-r–r– 1 root root 0 Sep 10 03:36 /proc/scsi/lpfc/0

Yet another option is to check if kernel module is installed or not

# lsmod | grep -i lpfc
lpfc 170561 0
scsi_transport_fc 12353 1 lpfc
scsi_mod 120269 5 scsi_dump,lpfc,scsi_transport_fc,cciss,sd_mod