Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi Carson, Thanks for your reply. It is certainly odd that a write-ahead-cache should make DRBD slower rather than faster. The comments I picked up were from Lars Ellenberg: http://thread.gmane.org/gmane.linux.network.drbd/11397/focus=11401 "no. more concern about your write cache in the cciss controller, and whether it lies to the kernel about having written stuff to disk when in fact it is only in that (probably not battery backed?) write cache..." The fact is that I have a cciss RAID controller with write-ahead-cache. I was experiencing DRBD locking. Having changed DRBD to use the setting in this posting, so far I am not getting locking. Is this related to my cciss?, or my network cards?, (which were certainly contributing), I really don't know :) But so far my problems are fixed and I don't have any more locking... Ben Carson Gaspar wrote: > Ben Clewett wrote: > ... >> For those of you having locking and following this thread, I have >> found another problem related to our HP Proliant servers. >> >> These optionally come with a battery backed up write-ahead-cache on >> the cciss controller. I have 256M of write ahead cache active. >> >> I found this thread from Lars suggesting these items may have a >> problem where they miss-report storage of data: >> >> http://lists.linbit.com/pipermail/drbd-user/2007-June/007033.html > > There is no problem, as long as your write cache is battery backed. If > it isn't, you're risking your data. But that isn't your performance > problem (it makes things faster, not slower...). It may, however, make > your performance uneven. Increasing your buffers allows drbd to queue > more data, and smooths out the cciss driver's response time impact. > ************************************************************************* This e-mail is confidential and may be legally privileged. It is intended solely for the use of the individual(s) to whom it is addressed. Any content in this message is not necessarily a view or statement from Road Tech Computer Systems Limited but is that of the individual sender. If you are not the intended recipient, be advised that you have received this e-mail in error and that any use, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. We use reasonable endeavours to virus scan all e-mails leaving the company but no warranty is given that this e-mail and any attachments are virus free. You should undertake your own virus checking. The right to monitor e-mail communications through our networks is reserved by us Road Tech Computer Systems Ltd. Shenley Hall, Rectory Lane, Shenley, Radlett, Hertfordshire, WD7 9AN. - VAT Registration No GB 449 3582 17 Registered in England No: 02017435, Registered Address: Charter Court, Midland Road, Hemel Hempstead, Hertfordshire, HP2 5GE. *************************************************************************