Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
Bill Sommerfeld writes: > On Wed, 2008-10-22 at 10:30 +0100, Darren J Moffat wrote: > > I'm assuming this is local filesystem rather than ZFS backed NFS (which > > is what I have). > > Correct, on a laptop. > > > What has setting the 32KB recordsize done for the rest of your home > > dir, or did you give the evolution directory its own dataset ? > > The latter, though it occurs to me that I could set the recordsize back > up to 128K once the databases (one per mail account) are created -- the > recordsize dataset property is read only at file create time when the > file's recordsize is set. ...almost. The definitive recordsize for a file is set when the filesize grows, for the first time, above the filessystem recordsize property. Touching a file is not enough here. > (Having a new interface to set the file's > recordsize directly at create time would bypass this sort of gyration). > I kind of agree here but we would need to change also how it works also. -r > (Apparently the sqlite file format uses 16-bit within-page offsets; 32kb > is its current maximum page size and 64k may be as large as it can go > without significant renovations..) > > - Bill > > > - Bill > > ___ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
On Wed, Oct 22, 2008 at 04:31:43PM -0500, Nicolas Williams wrote: > On Wed, Oct 22, 2008 at 11:05:09PM +0200, Kees Nuyt wrote: > > Just a remark: > > Increasing the SQLite page_size while keeping the same > > [default_]cache_size will effectively increase the amount of memory > > allocated to the SQLite cache, because the SQLite cache_size is > > expressed in pages. > > IMHO, for a fair performance comparison, one should half the > > cache_size when the page_size is doubled. > > I'm not sure that I agree. While the cache gets larger if you increase > the page size, the cache nonetheless caches the same number of integral > pages. Each miss requires reading a whole page, and each addition to > the cache, when full, requires evicting another. On second thought, making the sqlite cache thrash != thrashing the disk. The filesystem cache will still help -- there will be more data copies or VM page flips, but that's probably OK. I'll see how to make the default cache_size determination take the DB's page_size into account. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
On Wed, Oct 22, 2008 at 11:05:09PM +0200, Kees Nuyt wrote: > [Default] On Tue, 21 Oct 2008 15:43:08 -0400, Bill Sommerfeld > <[EMAIL PROTECTED]> wrote: > > >On Mon, 2008-10-20 at 16:57 -0500, Nicolas Williams wrote: > >> > >> I've a report that the mismatch between SQLite3's default block size > >> and ZFS' causes some performance problems for Thunderbird users. > > > > I was seeing a severe performance problem with sqlite3 databases > > as used by evolution (not thunderbird). > > > > It appears that reformatting the evolution databases to a 32KB database > > page size and setting zfs's record size to a matching 32KB has done > > wonders for evolution performance to a ZFS home directory. > > Just a remark: > Increasing the SQLite page_size while keeping the same > [default_]cache_size will effectively increase the amount of memory > allocated to the SQLite cache, because the SQLite cache_size is > expressed in pages. > IMHO, for a fair performance comparison, one should half the > cache_size when the page_size is doubled. I'm not sure that I agree. While the cache gets larger if you increase the page size, the cache nonetheless caches the same number of integral pages. Each miss requires reading a whole page, and each addition to the cache, when full, requires evicting another. Going from 1KB pages to 32KB pages would require going from cache_size=2000 to cache_size=62 by your logic, but 64 is a rather small number -- sure there will be so many evictions for a sufficiently large DB (at least 2MB) that you'll be thrashing. Conversely, 64MB of cache is a lot for most of the apps we're talking about, so perhaps I should leave the max default page size at 8KB. Nico -- ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
[Default] On Tue, 21 Oct 2008 15:43:08 -0400, Bill Sommerfeld <[EMAIL PROTECTED]> wrote: >On Mon, 2008-10-20 at 16:57 -0500, Nicolas Williams wrote: >> >> I've a report that the mismatch between SQLite3's default block size >> and ZFS' causes some performance problems for Thunderbird users. > > I was seeing a severe performance problem with sqlite3 databases > as used by evolution (not thunderbird). > > It appears that reformatting the evolution databases to a 32KB database > page size and setting zfs's record size to a matching 32KB has done > wonders for evolution performance to a ZFS home directory. Just a remark: Increasing the SQLite page_size while keeping the same [default_]cache_size will effectively increase the amount of memory allocated to the SQLite cache, because the SQLite cache_size is expressed in pages. IMHO, for a fair performance comparison, one should half the cache_size when the page_size is doubled. [snip] > > - Bill > -- ( Kees Nuyt ) c[_] ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
On Wed, 2008-10-22 at 10:30 +0100, Darren J Moffat wrote: > I'm assuming this is local filesystem rather than ZFS backed NFS (which > is what I have). Correct, on a laptop. > What has setting the 32KB recordsize done for the rest of your home > dir, or did you give the evolution directory its own dataset ? The latter, though it occurs to me that I could set the recordsize back up to 128K once the databases (one per mail account) are created -- the recordsize dataset property is read only at file create time when the file's recordsize is set. (Having a new interface to set the file's recordsize directly at create time would bypass this sort of gyration). (Apparently the sqlite file format uses 16-bit within-page offsets; 32kb is its current maximum page size and 64k may be as large as it can go without significant renovations..) - Bill - Bill ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
Bill Sommerfeld wrote: > On Mon, 2008-10-20 at 16:57 -0500, Nicolas Williams wrote: >> I've a report that the mismatch between SQLite3's default block size and >> ZFS' causes some performance problems for Thunderbird users. > > I was seeing a severe performance problem with sqlite3 databases as used > by evolution (not thunderbird). > > It appears that reformatting the evolution databases to a 32KB database > page size and setting zfs's record size to a matching 32KB has done > wonders for evolution performance to a ZFS home directory. I'm assuming this is local filesystem rather than ZFS backed NFS (which is what I have). What as setting the 32KB recordsize done for the rest of your home dir, or did you give the evolution directory its own dataset ? -- Darren J Moffat ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
Hello Nicolas, Monday, October 20, 2008, 10:57:22 PM, you wrote: NW> I've a report that the mismatch between SQLite3's default block size and NW> ZFS' causes some performance problems for Thunderbird users. NW> It'd be great if there was an API by which SQLite3 could set its block NW> size to match the hosting filesystem or where it could set the DB file's NW> record size to match the SQLite3/app default block size (1KB). NW> Is there such an API? If not, is there an RFE I could add a call record NW> to? Maybe it would be also useful to provide an extra API so application could set zfs recordsize for a given file instead a file system wide propery (which should be a maximum allowed value). That way, assuming MySQL, Oracle and other would start using such an extension, Oracle would ask ZFS to match its recordsize to db_block_size automatically and OOTB user experience would be much better. -- Best regards, Robert Milkowskimailto:[EMAIL PROTECTED] http://milek.blogspot.com ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
On Tue, Oct 21, 2008 at 03:43:08PM -0400, Bill Sommerfeld wrote: > On Mon, 2008-10-20 at 16:57 -0500, Nicolas Williams wrote: > > I've a report that the mismatch between SQLite3's default block size and > > ZFS' causes some performance problems for Thunderbird users. > > I was seeing a severe performance problem with sqlite3 databases as used > by evolution (not thunderbird). > > It appears that reformatting the evolution databases to a 32KB database > page size and setting zfs's record size to a matching 32KB has done > wonders for evolution performance to a ZFS home directory. > > > It'd be great if there was an API by which SQLite3 could set its block > > size to match the hosting filesystem or where it could set the DB file's > > record size to match the SQLite3/app default block size (1KB). > > IMHO some of the fix has to involve sqlite3 using a larger page size by > default when creating the database -- it seems to be a lot more > efficient with the larger page size. > > Databases like sqlite3 are being used "under the covers" by growing > numbers of applications -- it seems like there's a missing interface > here if we want decent out-of-the-box performance of end-user apps like > tbird and evolution using databases on zfs. Agreed. I've filed: 3452: os_unix.c:unixSectorSize() should use statvfs() to get pref blk size http://www.sqlite.org/cvstrac/tktview?tn=3452 3454: hardcoded 32KB pagesize max may be too low http://www.sqlite.org/cvstrac/tktview?tn=3454 and 6762083 sqlite3 default pagesize selection could be better (SQLite3 tickets #3452 and 3454) Nico -- ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
On Mon, 2008-10-20 at 16:57 -0500, Nicolas Williams wrote: > I've a report that the mismatch between SQLite3's default block size and > ZFS' causes some performance problems for Thunderbird users. I was seeing a severe performance problem with sqlite3 databases as used by evolution (not thunderbird). It appears that reformatting the evolution databases to a 32KB database page size and setting zfs's record size to a matching 32KB has done wonders for evolution performance to a ZFS home directory. > It'd be great if there was an API by which SQLite3 could set its block > size to match the hosting filesystem or where it could set the DB file's > record size to match the SQLite3/app default block size (1KB). IMHO some of the fix has to involve sqlite3 using a larger page size by default when creating the database -- it seems to be a lot more efficient with the larger page size. Databases like sqlite3 are being used "under the covers" by growing numbers of applications -- it seems like there's a missing interface here if we want decent out-of-the-box performance of end-user apps like tbird and evolution using databases on zfs. - Bill ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Setting per-file record size / querying fs/file record size?
On Mon, Oct 20, 2008 at 04:57:22PM -0500, Nicolas Williams wrote: > I've a report that the mismatch between SQLite3's default block size and > ZFS' causes some performance problems for Thunderbird users. > > It'd be great if there was an API by which SQLite3 could set its block > size to match the hosting filesystem or where it could set the DB file's > record size to match the SQLite3/app default block size (1KB). > > Is there such an API? If not, is there an RFE I could add a call record > to? To answer one of my own questions: I can use statvfs(2) to discover the preferred block size of a filesystem. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] Setting per-file record size / querying fs/file record size?
I've a report that the mismatch between SQLite3's default block size and ZFS' causes some performance problems for Thunderbird users. It'd be great if there was an API by which SQLite3 could set its block size to match the hosting filesystem or where it could set the DB file's record size to match the SQLite3/app default block size (1KB). Is there such an API? If not, is there an RFE I could add a call record to? Nico -- ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
