Does BAARF apply to RAID6?

Posted in 2010

Topics: Performance & Tuning, Platform-Specific Issues

Konikoff, Robert W Mr CIV US USA AMC — Mon, 04 Oct 2010 13:31:36 — source: IIUG Forums & Mailing Lists

HP-UX 11.iv3 IDS 11.5 Yes or No? If No, why? Does BAARF apply to RAID 6? I'm told the performance hit isn't nearly as bad as RAID 5, and the safety factor for recovery is better if you have a hardware failure. Thanks. Rob

↪ replying to Konikoff, Robert W Mr CIV US USA AMC

Art Kagel — Mon, 04 Oct 2010 13:35:53 — source: IIUG Forums & Mailing Lists

Raid6 is just raid5 with second parity block. Performance and safety are the same AFAIK. Art On Oct 4, 2010 9:31 AM, "Konikoff, R...." <rob.konikoff@us.army.mil> wrote: > HP-UX 11.iv3 > IDS 11.5 > > Yes or No? If No, why? > Does BAARF apply to RAID 6? > > I'm told the performance hit isn't nearly as bad as RAID 5, and the > safety factor for recovery is better if you have a hardware failure. > > Thanks. > > Rob > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > --00163631053f6766340491ca9fac

↪ replying to Art Kagel

Konikoff, Robert W Mr CIV US USA — Mon, 04 Oct 2010 13:46:09 — source: IIUG Forums & Mailing Lists

Art: Thanks for the rapid response. Our development team is adamant about using something called 'Data Protector' to run a virtual disk level copy to an off site, then having the database 'pick up' the new disk space. I'm not sure how this is going to work. Doesn't IDS 11.5 have a mechanism for sending a transaction level record? Right now, I'm collecting info so I can educate my self. I'm still using a 7.3x and I'm not that in tune with the 11.5. Thank you. Rob -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Art Kagel Sent: Monday, October 04, 2010 9:36 AM To: ids@iiug.org Subject: Re: Does BAARF apply to RAID6? [21528] Raid6 is just raid5 with second parity block. Performance and safety are the same AFAIK. Art On Oct 4, 2010 9:31 AM, "Konikoff, R...." <rob.konikoff@us.army.mil> wrote: > HP-UX 11.iv3 > IDS 11.5 > > Yes or No? If No, why? > Does BAARF apply to RAID 6? > > I'm told the performance hit isn't nearly as bad as RAID 5, and the > safety factor for recovery is better if you have a hardware failure. > > Thanks. > > Rob > > > **************************************************************************** *** > Forum Note: Use "Reply" to post a response in the discussion forum. > --00163631053f6766340491ca9fac **************************************************************************** *** Forum Note: Use "Reply" to post a response in the discussion forum.

↪ replying to Konikoff, Robert W Mr CIV US USA

Art Kagel — Mon, 04 Oct 2010 14:39:41 — source: IIUG Forums & Mailing Lists

Um, be aware that using a SAN level copy of the Informix chunks as a disaster recovery option DOES NOT WORK if you are depending on the continuous copy feature of the SAN or the Data Protector software. It can ONLY work as a discrete external backup. That is, you have to tell the engine that you are making a copy by running "onmode -c block" to sync all of the server's dirty pages to disk and stop any new writes to disk during the copy. Then you can make a safe and usable discrete copy to a remote site and release the engine using "onmode -c unblock". This is because the engine will mark the root chunk's header page with the engine's status on disk and dirty pages will not have been synced to disk. The server will either refuse to startup from such a continuous copy or will be inconsistent internally and may crash later. If they insist that "No, no, no. They say they work with Informix. This will work!" run it by IBM Tech Support first before you depend on it! IBM will know if the so called Data Protector will make usable copies or not. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Mon, Oct 4, 2010 at 9:46 AM, Konikoff, R.... <rob.konikoff@us.army.mil>wrote: > Art: > > Thanks for the rapid response. > > Our development team is adamant about using something called 'Data > Protector' to run a virtual disk level copy to an off site, then having the > database 'pick up' the new disk space. > > I'm not sure how this is going to work. Doesn't IDS 11.5 have a mechanism > for sending a transaction level record? Right now, I'm collecting info so I > can educate my self. > > I'm still using a 7.3x and I'm not that in tune with the 11.5. > > Thank you. > > Rob > > -----Original Message----- > From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Art > Kagel > Sent: Monday, October 04, 2010 9:36 AM > To: ids@iiug.org > Subject: Re: Does BAARF apply to RAID6? [21528] > > Raid6 is just raid5 with second parity block. Performance and safety are > the > > same AFAIK. > > Art > On Oct 4, 2010 9:31 AM, "Konikoff, R...." <rob.konikoff@us.army.mil> > wrote: > > HP-UX 11.iv3 > > IDS 11.5 > > > > Yes or No? If No, why? > > Does BAARF apply to RAID 6? > > > > I'm told the performance hit isn't nearly as bad as RAID 5, and the > > safety factor for recovery is better if you have a hardware failure. > > > > Thanks. > > > > Rob > > > > > > > > > **************************************************************************** > *** > > > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > --00163631053f6766340491ca9fac > > > **************************************************************************** > *** > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --00163630edf38e76080491cb83dc

↪ replying to Art Kagel

Konikoff, Robert W Mr CIV US USA — Mon, 04 Oct 2010 15:42:04 — source: IIUG Forums & Mailing Lists

Once again, Art, your advice is on target. I know where to dig from here. Thanks again! Rob -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Art Kagel Sent: Monday, October 04, 2010 10:40 AM To: ids@iiug.org Subject: Re: Does BAARF apply to RAID6? [21532] Um, be aware that using a SAN level copy of the Informix chunks as a disaster recovery option DOES NOT WORK if you are depending on the continuous copy feature of the SAN or the Data Protector software. It can ONLY work as a discrete external backup. That is, you have to tell the engine that you are making a copy by running "onmode -c block" to sync all of the server's dirty pages to disk and stop any new writes to disk during the copy. Then you can make a safe and usable discrete copy to a remote site and release the engine using "onmode -c unblock". This is because the engine will mark the root chunk's header page with the engine's status on disk and dirty pages will not have been synced to disk. The server will either refuse to startup from such a continuous copy or will be inconsistent internally and may crash later. If they insist that "No, no, no. They say they work with Informix. This will work!" run it by IBM Tech Support first before you depend on it! IBM will know if the so called Data Protector will make usable copies or not. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Mon, Oct 4, 2010 at 9:46 AM, Konikoff, R.... <rob.konikoff@us.army.mil>wrote: > Art: > > Thanks for the rapid response. > > Our development team is adamant about using something called 'Data > Protector' to run a virtual disk level copy to an off site, then having the > database 'pick up' the new disk space. > > I'm not sure how this is going to work. Doesn't IDS 11.5 have a mechanism > for sending a transaction level record? Right now, I'm collecting info so I > can educate my self. > > I'm still using a 7.3x and I'm not that in tune with the 11.5. > > Thank you. > > Rob > > -----Original Message----- > From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Art > Kagel > Sent: Monday, October 04, 2010 9:36 AM > To: ids@iiug.org > Subject: Re: Does BAARF apply to RAID6? [21528] > > Raid6 is just raid5 with second parity block. Performance and safety are > the > > same AFAIK. > > Art > On Oct 4, 2010 9:31 AM, "Konikoff, R...." <rob.konikoff@us.army.mil> > wrote: > > HP-UX 11.iv3 > > IDS 11.5 > > > > Yes or No? If No, why? > > Does BAARF apply to RAID 6? > > > > I'm told the performance hit isn't nearly as bad as RAID 5, and the > > safety factor for recovery is better if you have a hardware failure. > > > > Thanks. > > > > Rob > > > > > > > > > **************************************************************************** > *** > > > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > --00163631053f6766340491ca9fac > > > **************************************************************************** > *** > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > **************************************************************************** *** > Forum Note: Use "Reply" to post a response in the discussion forum. > > --00163630edf38e76080491cb83dc **************************************************************************** *** Forum Note: Use "Reply" to post a response in the discussion forum.