Re: SMS Advanced Feature
Jason, > We are planning to implement SMS data compression. I've read that we > cannot implement compression on VSAM file that is open for update. Is > this true? Aside from this, any other considerations? > Compression will not take place until you recreate the vsam dataset. The danger with updating a compressed vsam dataset is that you will likely change the size of the data and an increase could cause you to incur a CI split. Otherwise you can compress a vsam dataset that is updated. We looked at using compression but determined that CPU costs exceeded what we saved in dasd costs. Your mileage may vary. Regards, John -- 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: SMS Advanced Feature
We have seen an ongoing problem (through 1.7) where C programs cannot reliably read compressed files. The programs apparently perceive an end of file before the data ends. -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Jason To Sent: Tuesday, November 13, 2007 11:43 PM To: IBM-MAIN@BAMA.UA.EDU Subject: SMS Advanced Feature We are planning to implement SMS data compression. I've read that we cannot implement compression on VSAM file that is open for update. Is this true? Aside from this, any other considerations? Jason NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. -- 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: SMS Advanced Feature
Hi John, Thanks for the info and confirmation. From the book, it looks like it did mentioned about cannot implement compression on dataset open for update but later realized it was actually for QSAM etc and not VSAM. We have also already tested to compressed VSAM files that is open for update and confirmed that it has no problem. Jason Quoting John Kington <[EMAIL PROTECTED]>: Jason, We are planning to implement SMS data compression. I've read that we cannot implement compression on VSAM file that is open for update. Is this true? Aside from this, any other considerations? Compression will not take place until you recreate the vsam dataset. The danger with updating a compressed vsam dataset is that you will likely change the size of the data and an increase could cause you to incur a CI split. Otherwise you can compress a vsam dataset that is updated. We looked at using compression but determined that CPU costs exceeded what we saved in dasd costs. Your mileage may vary. Regards, John -- 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: SMS Advanced Feature
We found using both DFSMS compression and striping or Innovation IAM compression that in most cases we gain significantly in performance and save DASD as a side benefit with compression. The CPU increase to write the data was more than offset by the performance gains and only moderate increase in CPU to read the data. Best Regards, Sam Knutson, GEICO System z Performance and Availability mailto:[EMAIL PROTECTED] (office) 301.986.3574 "Think big, act bold, start simple, grow fast..." -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of John Kington Sent: Wednesday, November 14, 2007 8:10 AM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: SMS Advanced Feature Jason, > We are planning to implement SMS data compression. I've read that we > cannot implement compression on VSAM file that is open for update. Is > this true? Aside from this, any other considerations? > Compression will not take place until you recreate the vsam dataset. The danger with updating a compressed vsam dataset is that you will likely change the size of the data and an increase could cause you to incur a CI split. Otherwise you can compress a vsam dataset that is updated. We looked at using compression but determined that CPU costs exceeded what we saved in dasd costs. Your mileage may vary. Regards, John This email/fax message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution of this email/fax is prohibited. If you are not the intended recipient, please destroy all paper and electronic copies of the original message. -- 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
