| From: | Ravi Krishna <s(dot)ravikrishna(at)aim(dot)com> |
|---|---|
| To: | tgl(at)sss(dot)pgh(dot)pa(dot)us |
| Cc: | pgsql-admin(at)postgresql(dot)org |
| Subject: | Re: WAL and O_DIRECT |
| Date: | 2015-05-14 16:07:04 |
| Message-ID: | 14d532dde85-2108-310a1@webstg-m03.mail.aol.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-admin |
>> However our DB2 folks are raising a concern that PG WAL writes may not be crash safe, unless we are using
>> write back technology in SAN or SSD , which we are using.
> What's your point exactly? If the underlying hardware does not provide durable writes, there's
> nothing PG (or DB2) can do to fix that.
Am I right in concluding that PG WAL writes without underlying h/w caching is not crash proof.
Fortunately these days caching is ubiquitous in all SSD/SAN technology. Both Oracle and DB2 always open WAL
logs in O_DIRECT. Is this thinking outdated with modern technology which caches writes. Wonder why Oracle/DB2
are not making O_DIRECT optional. I am sure it will increase the write performance.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2015-05-14 16:25:28 | Re: WAL and O_DIRECT |
| Previous Message | Tom Lane | 2015-05-14 15:55:33 | Re: WAL and O_DIRECT |