I mostly agree. I've been in shops with 10+ year old DASD, so they might still customers using structured log file DASD. You need to how your DASD works, in order to develop a reliable erasure plan.
However, I had a teammate delete the virtual volumes on old shark prior to erasing the data. Would simply reallocating the volumes (assuming it would put them back in the same spot) and erasing them, reliably remove all of the data? I'm not smart enough to know for sure. Then you have to know how the DASD handles bad tracks/sectors. There could be residual data in bad tracks/sectors that have been replaced. How do you erase the no longer used bad tracks? I know that most DASD has spare sectors on each track, so erasing the track probably erases the bad sectors as well. But I'm not smart enough to know for sure. Whether or not you consult an expert depends on how sure you need to be that the every last bit of your data has been completely and throughly erased or made unreadable. Where I currently work, I don't have to worry about erasing DASD. They require that all of the old DASD be crushed and shreaded. -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of R.S. Sent: Wednesday, December 12, 2012 5:25 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: dsf to write over entire volume W dniu 2012-12-12 18:04, Don Williams pisze: > ICKDSF is not intended to erase volumes. But it can erase the volumes, can't it? > Now days, DASD volumes tend to be "virtual". Virtual volume still contain real data. Excluding passing away "structured log file" technology (RVA, SVA), when you erase the logical (virtual) volume, you overwrite the real data. > Only the DASD controller may know on which real hard drives your > logical volumes are actually located and spread across. Not only controller. Sometimes smart folks also know that. I'm not so smart, but I can tell you what is the relationship between physical discs and logical volumes in my array. I have it documented, and it can be checked/confirmed. > To be sure that your data is actually erased, you may need to consult > with the vendor or other expert of your particular type of DASD. It need not to be an expert. Last but not least: when you are going to dispose whole array, the choice is obvious: erase all logical volumes, isn't it? > If the DASD is encrypted, you may be able to "erase" the encryption keys > making the DASD effectively unreadable. Good assumption, unfortunately bad implementation. There are errors in "secure erase" implementation, at least for some disks, AFAIK. There nothing worse than false certainty in such area. My €0.02 -- Radoslaw Skorupka Lodz, Poland -- Tre tej wiadomoci moe zawiera informacje prawnie chronione Banku przeznaczone wycznie do uytku subowego adresata. Odbiorc moe by jedynie jej adresat z wyczeniem dostpu osób trzecich. Jeeli nie jeste adresatem niniejszej wiadomoci lub pracownikiem upowanionym do jej przekazania adresatowi, informujemy, e jej rozpowszechnianie, kopiowanie, rozprowadzanie lub inne dziaanie o podobnym charakterze jest prawnie zabronione i moe by karalne. Jeeli otrzymae t wiadomo omykowo, prosimy niezwocznie zawiadomi nadawc wysyajc odpowied oraz trwale usun t wiadomo wczajc w to wszelkie jej kopie wydrukowane lub zapisane na dysku. This e-mail may contain legally privileged information of the Bank and is intended solely for business use of the addressee. This e-mail may only be received by the addressee and may not be disclosed to any third parties. If you are not the intended addressee of this e-mail or the employee authorised to forward it to the addressee, be advised that any dissemination, copying, distribution or any other similar activity is legally prohibited and may be punishable. If you received this e-mail by mistake please advise the sender immediately by using the reply facility in your e-mail software and delete permanently this e-mail including any copies of it either printed or saved to hard drive. BRE Bank SA, 00-950 Warszawa, ul. Senatorska 18, tel. +48 (22) 829 00 00, fax +48 (22) 829 00 33, www.brebank.pl, e-mail: i...@brebank.pl Sd Rejonowy dla m. st. Warszawy XII Wydzia Gospodarczy Krajowego Rejestru Sdowego, nr rejestru przedsibiorców KRS 0000025237, NIP: 526-021-50-88. Wedug stanu na dzie 01.01.2012 r. kapita zakadowy BRE Banku SA (w caoci wpacony) wynosi 168.410.984 zotych. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
