Benchmarks Of ZFS-FUSE On Linux Against EXT4, Btrfs

[allquixotic]

Oh, I just wanted to chime in and say that, for my own dedicated server, I'm running a hardware RAID controller (Adaptec 5405 if you're interested) with four 1.5TB Seagate SATA disks, on Ubuntu 10.04.1 Server. I'm using the XFS filesystem due to the way it is tuned for smooth I/O performance and parallel access; I don't need the raw throughput of ext4, but I do need data safety and "fair" scheduling of I/O across processes, two things XFS is very good at.

I was using ext4 on Software RAID5 before, but I realized my mistake when I was able to quadruple my write performance by moving to Hardware RAID10 and XFS.

I don't think I will be upgrading anything as low-level as the filesystem on my server for at least a year (I tolerated the ext4 for a year before I tossed it), but if I ever do, I will definitely have to re-evaluate my options and see if btrfs has matured or if native ZFS on Linux is a reality.

[FeRD_NYC]

Another small typo in the article. In the text below the IOZone 8GB write test chart (second chart on page 4), judging by the image it's meant to read:

When carrying out an 8GB write test with a 64Kb block size in IOzone, EXT4 and Btrfs were 1.64~1.67x faster than ZFS-FUSE.

[edogawaconan]

What's your business case for a transfer that is going to take 30 minutes but yet may have been altered from when you started? If you're looking to back up something like a transactional database making copies of open files is not the way to be going.

guess what - it is doable with zfs. Just because your filesystem of choice can't do it, it doesn't mean that it is impossible to do.

[locovaca]

guess what - it is doable with zfs. Just because your filesystem of choice can't do it, it doesn't mean that it is impossible to do.

It's doable doesn't means it's good practice. It's doable to strip PAM out of Linux and run everything as root, too. Making and trusting backups of open files is very bad business. There is no guarantee that the application has those files in any sort of useable state.

[edogawaconan]

It's doable doesn't means it's good practice. It's doable to strip PAM out of Linux and run everything as root, too. Making and trusting backups of open files is very bad business. There is no guarantee that the application has those files in any sort of useable state.

Then guess why it's on the mysql page...

[korpenkraxar]

ext4 + lvm2 on top of your raid configuration of choice and you are done sir.
and this way protects you also from the screw ups of the filesystem itself.

Well apparently that was not allowed according to the OP

[edogawaconan]

Well apparently that was not allowed according to the OP

At least one person claimed that lvm in snapshot mode killed performance. A benchmark to confirm this would be nice

[korpenkraxar]

Then guess why it's on the mysql page...

Yes it says it is possible but nothing about whether or not it is safe. I guess the objection would be that a database consists of disk state + CPU/RAM state at any point during operation. You can backup a snapshot of the disk but not the other activities at a given point in time.

[locovaca]

Then guess why it's on the mysql page...

w00t, a cron script to create a backup of a database and copy it over ssh. Totally innovative and automatic. Thanks ZFS!

Of course, if were to page forward, you'd see stuff like this:

3.

Start up mysqld on the slave. If you are using InnoDB, Falcon or Maria you should get auto-recovery, if it is needed, to make sure the table data is correct, as shown here when I started up from our mid-INSERT snapshot:

InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
081109 15:59:59 InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
081109 16:00:03 InnoDB: Started; log sequence number 0 1142807951
081109 16:00:03 [Note] /slavepool/mysql-5.0.67-solaris10-i386/bin/mysqld: ready for connections.
Version: '5.0.67' socket: '/tmp/mysql.sock' port: 3306 MySQL Community Server (GPL)

On MyISAM, or other tables, you may need to run REPAIR TABLE, and you might even have lost some information. You should use a recovery-capable storage engine and a regular synchronization schedule to reduce the risk for significant data loss.

Uhm, no thanks. I don't shut down my machines by flicking the switch on the power strip, and I don't backup my databases by doing the same.

[edogawaconan]

Uhm, no thanks. I don't shut down my machines by flicking the switch on the power strip, and I don't backup my databases by doing the same.

If you actually know how database works, you should know that it's normal. Unless you're using crappy database, that is (mysql with myisam engine).