Re: z/OS DFS SMB Performance
Smith, Sean M wrote: Yes I believe that is the case. We are not using z/OS for the VPN service. In that case you should notice similar speeds on same speed link, with or without VPN. I know your non-VPN connection is LAN connection, probably much faster than VPN connection. If possible try to connect via VPN locally and compare the speed with direct connection. Don't compare i.e ftp speed to SMB speed, SMB is not fast. How can VPN influence SMB performance (my guesses): 1. Different (smaller) IP packets causing worse performance. 2. Additional data in packets causing overhead: you SMB transmit 100kB, VPN transmit it as 130kB. 3. VPN devices are CPU-overloaded with encryption/decryption. 4. VPN does not like SMB vbg It Windows-like technology... -- Radoslaw Skorupka Lodz, Poland -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
z/OS DFS SMB Performance
Problem: When connecting to work over VPN, SMB performance leaves a lot to be desired. Where a 200k file in the office loads in 5-9 seconds, over VPN it takes 50-60 seconds. It does not appear to be a server problem or a bandwidth problem. I tried the same file directly pulling it from an HFS and I got it loaded in 6 seconds from home. I then setup a file server on a z/OS box to see if it would perform better. It did not. Talking to local VPN expert, he basically said that SMB is chatty and that we will see some improvement with Windows Vista. Reading the DFS manual for SMB, there are several notes about performance one of which states that HEAPPOOLS(ON) provides a significant improvement. What they don't say is what the heap pool sizes and percentages should be for SMB. I am overriding the HEAPPOOLS in the JCL so these will not be system wide. I tried HEAPPOOLS(ON) and did see a good improvement. Any help would be appreciated. Sean Smith Bank of America -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: z/OS DFS SMB Performance
Is the VPN terminated outside from z/OS ? I mean: [1]---encrypted-Inet--- [2] ---clearLAN--- [3] 1 - remote PC with VPN 2 - local VPN device 3 - mainframe Is the above true ? -- Radoslaw Skorupka Lodz, Poland Smith, Sean M wrote: Problem: When connecting to work over VPN, SMB performance leaves a lot to be desired. Where a 200k file in the office loads in 5-9 seconds, over VPN it takes 50-60 seconds. It does not appear to be a server problem or a bandwidth problem. I tried the same file directly pulling it from an HFS and I got it loaded in 6 seconds from home. I then setup a file server on a z/OS box to see if it would perform better. It did not. Talking to local VPN expert, he basically said that SMB is chatty and that we will see some improvement with Windows Vista. Reading the DFS manual for SMB, there are several notes about performance one of which states that HEAPPOOLS(ON) provides a significant improvement. What they don't say is what the heap pool sizes and percentages should be for SMB. I am overriding the HEAPPOOLS in the JCL so these will not be system wide. I tried HEAPPOOLS(ON) and did see a good improvement. Any help would be appreciated. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: z/OS DFS SMB Performance
Yes I believe that is the case. We are not using z/OS for the VPN service. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of R.S. Sent: Thursday, March 30, 2006 10:29 AM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: z/OS DFS SMB Performance Is the VPN terminated outside from z/OS ? I mean: [1]---encrypted-Inet--- [2] ---clearLAN--- [3] 1 - remote PC with VPN 2 - local VPN device 3 - mainframe Is the above true ? -- Radoslaw Skorupka Lodz, Poland Smith, Sean M wrote: Problem: When connecting to work over VPN, SMB performance leaves a lot to be desired. Where a 200k file in the office loads in 5-9 seconds, over VPN it takes 50-60 seconds. It does not appear to be a server problem or a bandwidth problem. I tried the same file directly pulling it from an HFS and I got it loaded in 6 seconds from home. I then setup a file server on a z/OS box to see if it would perform better. It did not. Talking to local VPN expert, he basically said that SMB is chatty and that we will see some improvement with Windows Vista. Reading the DFS manual for SMB, there are several notes about performance one of which states that HEAPPOOLS(ON) provides a significant improvement. What they don't say is what the heap pool sizes and percentages should be for SMB. I am overriding the HEAPPOOLS in the JCL so these will not be system wide. I tried HEAPPOOLS(ON) and did see a good improvement. Any help would be appreciated. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: z/OS DFS SMB Performance
From my experience SMB on any platform is slow. Think about it, a 200K file loading in 5-9 seconds in the office. That is a transfer rate of somewhere between 20 to 40 K a second. Now add the overhead of a VPN and the latency and through put of something that is most likely much less than the network between your PC and the mainframe at your work. What is the slowest network connection in your office? What is the speed of the network that your VPN is transversing? What do you mean pulling it directly? FTP? FTP is much more efficient that SMB. SMB is real chatty. IIRC it does one ACK for every two data packets and the ACK is not sent until the data packets are received. This is on top of the TCP level ACK's. Smith, Sean M wrote: Problem: When connecting to work over VPN, SMB performance leaves a lot to be desired. Where a 200k file in the office loads in 5-9 seconds, over VPN it takes 50-60 seconds. It does not appear to be a server problem or a bandwidth problem. I tried the same file directly pulling it from an HFS and I got it loaded in 6 seconds from home. I then setup a file server on a z/OS box to see if it would perform better. It did not. Talking to local VPN expert, he basically said that SMB is chatty and that we will see some improvement with Windows Vista. Reading the DFS manual for SMB, there are several notes about performance one of which states that HEAPPOOLS(ON) provides a significant improvement. What they don't say is what the heap pool sizes and percentages should be for SMB. I am overriding the HEAPPOOLS in the JCL so these will not be system wide. I tried HEAPPOOLS(ON) and did see a good improvement. Any help would be appreciated. Sean Smith Bank of America -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: z/OS DFS SMB Performance
On Thu, 30 Mar 2006 20:29:15 -0500, John S. Giltner, Jr. [EMAIL PROTECTED] wrote: From my experience SMB on any platform is slow. Think about it, a 200K file loading in 5-9 seconds in the office. That is a transfer rate of somewhere between 20 to 40 K a second. Now add the overhead of a VPN and the latency and through put of something that is most likely much less than the network between your PC and the mainframe at your work. What is the slowest network connection in your office? What is the speed of the network that your VPN is transversing? What do you mean pulling it directly? FTP? FTP is much more efficient that SMB. SMB is real chatty. IIRC it does one ACK for every two data packets and the ACK is not sent until the data packets are received. This is on top of the TCP level ACK's. I had a presentation by cisco people about their VPN accelerator ,their AVS ( appl velocity system) their WAFS ( wan accelerator for file system) and WAE ( wan accelerator engine) , Obviously WAFS has been invented for the exact problem you are facing . The chat to open a document with word or excell over a network . The number they showed me was like 1000 exchanges to open and close a file and they were dividing this by 8 or 10 , by letting only the security portion of the handshaking flow ( enqueue etc .. ) and by simulating a big part of this handshaking on both ends to reduce the chatyness , and trying to let flow the data only . The improvement is just tremendous . try to find out on google how this WAFS , WAE and cisco accelerator work and it will give you some good insight in what John is describing exactly . Bruno Bruno(dot)sugliani(at)groupemornay(dot)asso(dot)fr -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
