What is a good SAN (or Cluster) File System for Windows XP?

[Smilin]

Originally posted by: Brazen

2. Better to mount the drive on a single box and share it out so that SMB oplocks can handle contention.

A very niche application (CAD software) requires block level access to the files, and an object level sharing protocol like SMB will not cut it.

Bullshit.

Frame taken from a capture with a block locked (oplocks otherwise disabled ... this capture is taken from a misconfigured/broken box that I was fixing yesterday)

638 07:33:27.216 000D2925167F 000BCD41907B SMB C lock & X, FID = 0x4004, Unlocks = 1 (0x00000000 for 0xFFFFFFFFFFFFFFFF) (xxxDeletedforPrivacyxxx) IP
FRAME: Base frame properties
FRAME: Time of capture = 8/30/2006 7:33:27 AM
FRAME: Time delta from previous physical frame: 31250 microseconds
FRAME: Frame number: 638
FRAME: Total frame length: 129 bytes
FRAME: Capture frame length: 129 bytes
FRAME: Frame data: Number of data bytes remaining = 129 (0x0081)
ETHERNET: EType = Internet IP (IPv4)
ETHERNET: Destination address = xxxDeletedforPrivacyxxx
ETHERNET: 0....... = Individual address
ETHERNET: .0...... = Universally administered address
ETHERNET: Source address = xxxDeletedforPrivacyxxx
ETHERNET: .0...... = Universally administered address
ETHERNET: Ethernet Type : 0x0800 (Internet IP (IPv4))
IP: Protocol = TCP - Transmission Control; Packet ID = 3895; Total IP Length = 115; Options = No Options
IP: Version = IPv4; Header Length = 20
IP: 0100.... = IP Version 4
IP: ....0101 = Header Length 20
IP: Type of Service = Normal Service
IP: 000..... = Precedence - Routine
IP: ...0.... = Normal Delay
IP: ....0... = Normal Throughput
IP: .....0.. = Normal Reliability
IP: ......0. = Normal Monetary Cost
IP: Total Length = 115 (0x73)
IP: Identification = 3895 (0xF37)
IP: Fragmentation Summary = 16384 (0x4000)
IP: .1.............. = Cannot fragment datagram
IP: ..0............. = Last fragment in datagram
IP: ...0000000000000 = Fragment Offset 0 (0x0000)
IP: Time to Live = 126 (0x7E)
IP: Protocol = TCP - Transmission Control
IP: Checksum = 32259 (0x7E03)
IP: Source Address = xxxDeletedforPrivacyxxx
IP: Destination Address = xxxDeletedforPrivacyxxx
TCP: Control Bits: .AP..., len: 75, seq:1026511329-1026511404, ack:3788195647, win:33103, src: 1150 dst: 445
TCP: Source Port = 0x047E
TCP: Destination Port = Microsoft-DS
TCP: Sequence Number = 1026511329 (0x3D2F51E1)
TCP: Acknowledgement Number = 3788195647 (0xE1CB473F)
TCP: Data Offset = 20 bytes
TCP: 0101.... = Data Offset (20 bytes)
TCP: ....0000 = Reserved bits
TCP: Flags = 0x18 : .AP...
TCP: ..0..... = No urgent data
TCP: ...1.... = Acknowledgement field significant
TCP: ....1... = Push function
TCP: .....0.. = No Reset
TCP: ......0. = No Synchronize
TCP: .......0 = Not the end of the data
TCP: Window = 33103 (0x814F)
TCP: Checksum = 0x17ED
TCP: Urgent Pointer = 0 (0x0)
NBT: SS: Session Message, Len: 71
NBT: Packet Type = Session Message
NBT: Packet Flags = 0 (0x0)
NBT: .......0 = Add 0 to Length
NBT: Packet Length = 71 (0x47)
NBT: SS Data: Number of data bytes remaining = 71 (0x0047)
SMB: C lock & X, FID = 0x4004, Unlocks = 1 (0x00000000 for 0xFFFFFFFFFFFFFFFF)
SMB: NT status code = 0x0, Facility = System, Severity = Success, Code = (0) STATUS_SUCCESS
SMB: NT Status Severity Code = Success
SMB: NT Status Customer Code = 0 (0x0)
SMB: NT Status Reserved Bit = 0 (0x0)
SMB: NT Status Facility = System
SMB: NT Status Code System Success = STATUS_SUCCESS
SMB: Header: PID = 0xFEFF TID = 0x4004 MID = 0x3041 UID = 0x7003
SMB: Tree ID (TID) = 16388 (0x4004)
SMB: Process ID (PID) = 65279 (0xFEFF)
SMB: User ID (UID) = 28675 (0x7003)
SMB: Multiplex ID (MID) = 12353 (0x3041)
SMB: Flags Summary = 24 (0x18)
SMB: .......0 = Lock & Read and Write & Unlock not supported
SMB: ......0. = Send No Ack not supported
SMB: ....1... = Using caseless pathnames
SMB: ...1.... = Canonicalized pathnames
SMB: ..0..... = No Opportunistic lock
SMB: .0...... = No Change Notify
SMB: 0....... = Client command
SMB: flags2 Summary = 51207 (0xC807)
SMB: ...............1 = Understands long filenames
SMB: ..............1. = Understands extended attributes
SMB: ...0............ = No DFS namespace
SMB: ..0............. = No paging of IO
SMB: .1.............. = Using NT status codes
SMB: 1............... = Using UNICODE strings
SMB: Unknown Flag2 bits = 2052 (0x804)
SMB: Command = C lock & X
SMB: Word count = 8
SMB: Word parameters
SMB: Next offset = 0xDEDE
SMB: File ID (FID) = 16388 (0x4004)
SMB: File name =\My Documents\Desktop.ini
SMB: Lock type = 0x0010
SMB: ...............0 = Lock out all access
SMB: ..............0. = not Oplock Break.
SMB: .............0.. = not Change Lock.
SMB: ............0... = not Cancel Lock
SMB: ...........1.... = Large File Lock.
SMB: Open timeout = -1
SMB: Number of unlocks = 1
SMB: Number of locks = 0
SMB: Byte count = 20
SMB: Byte parameters
SMB: Unlock range
SMB: Process ID (PID) = 65279 (0xFEFF)
SMB: File Offset (NT) = 0x0000000000000000
SMB: Lock Length (NT) = 0xFFFFFFFFFFFFFFFF
SMB: Command = No secondary command


Edit: This is actually kind of a crappy example since it was locking a single block in the file that consisted of the entire file!

Point was: SMB will handle locking portions of a file or the whole file. Give it a try

 

[bwnv]

my 02 cents
I run a real san server. 2 HP DL580's running mirrored scsi drives clustered, dual zeons. They drive an HP Smart array 1000 system: dual scsi channel 14 bays, dual redundant controllers 4 fiber links, one from each computer to each of the controllers. Everything is hot swap + hot spare, and all three have dual power supplies. All the disks are formatted using NTFS, but it could be anything else. The point is what makes a NAS is the equipment, not the file system.

 

[drag]

Originally posted by: bwnv
my 02 cents
I run a real san server. 2 HP DL580's running mirrored scsi drives clustered, dual zeons. They drive an HP Smart array 1000 system: dual scsi channel 14 bays, dual redundant controllers 4 fiber links, one from each computer to each of the controllers. Everything is hot swap + hot spare, and all three have dual power supplies. All the disks are formatted using NTFS, but it could be anything else. The point is what makes a NAS is the equipment, not the file system.

Well the thing is is that iSCSI is a protocol that is specificly designed to allow shared LUNs.

This means that you setup a target and it should allow multiple servers to access the same data at the same time on the same volume as if it is a local disk. Of course this requires some level of cooperation and syncronization between the various servers so they don't stomp all over themselves. This is the fundamental difference between something like NTFS vs Veritas CFS.

Now reading this thread and beleiving Smilin's comments I have come to this conclusion:

That with Windows maybe, and more likely Windows XP pro specificly there are some fundamental issues with sharing physicial volumes that can not be overcome by simply using a SAN (or cluster or whatever the hell you want to call it) file system.

That even when you do have the file systems level taken care of your very likely to run into other issues.

It seems that if your going to try to do this with Windows that your going to be best off by using a real server operating system like the higher end versions of Windows 2003 and carefully following a set of perscribed guidelines for your specific application. Either that or be willing to put a lot of time and effort into specificly testing to make sure that it's going to behaive properly.

Personally at home I run Linux desktop that boots up over gigabit ethernet using open-iscsi initiator and IET target (both software emulated i/o) and it works pretty well. Dead on reliable and it's fine with everything I throw at it, but I haven't tried any shared LUNs yet and am just using conventional XFS filing system.