harddisk too slow issue when recording 32 channels with logic pro

32 tracks mono 16 bit/48kHz: 25 MB/s; stereo 49 MB/s

32 mono 24/48: 37 MB/s; stereo 74 MB/s

So 197 MB/s should be enough. IF we're talking MegaBytes, not -bits...

I seem to remember that any sort of raid setup is NOT advantageous or even disadvantageous for audio recording; the streaming speed is rarely the bottleneck for recording audio, it is disk seek- and access times. Those can be longer on a raid setup -

(frowns)

Instead of half trying to half explain what I half remember, I chose to fully Google the article, so here it is:

http://www.soundonsound.com/sos/dec06/articles/applenotes_1206.htm

Drives formatted Mac OS Extended (Journaling Off) ?

It's also worth pointing out....

Thunderbolt and it's available bandwidth is not, by itself a guarantee of fast/optimal audio performance....

Other factors are just as important if not more so when purchasing and connecting a HD to a computer to be used for Audio streaming;

These factors are: (And this list is not exhaustive by any means..)

Rotational speed of the HD (7200rpm or greater is recommended)

Seek and Access times (The faster the better)

Continuous performance over time in regards to heat generated. (Some drives slow down the warmer they get so a well ventilated Drive enclosure is recommended!)

Is the drive partitioned? (Partitioning a drive adds to the latency of it's operation)

Is the drive one of the modern power saving types? (Green or 'varipower' type drives are notoriously 'bad' at streaming Audio because they put themselves to sleep or reduce performance at the slightly opportunity)

Number of Platters and Heads (Usually, the smaller the number of Platters, and the greater number of heads, the faster the seek and access time performance...)

Other slower HDs connected to the system can have an effect on the overall performance of your HD infrastructure depending on your configuration, how those drives are formatted and the setup of Spotlight. ( For example, Remove from Spotlight any drives that are formatted for MS DOS/Windows)

Finally, HD speed tests such as those provided by Blackmagic are not realistic indicators as to the sort of performance would would get using the HD in an Audio streaming situation. The only true way of knowing what the performance will be, of any given drive..is in real world usage...

Examples:

A single high performance 7200rpm 1GB non Green HD on the Firewire 800 bus will typically perform much better in regards to Audio streaming than a single 2GB 5400rpm HD on a Thunderbolt bus.

A single high performance 7200rpm 1GB non Green HD on the Firewire 800 bus will typically perform about the same as the exact same drive on a TB Bus

Several 5400rpm 2GB HDs will perform much better on a Thunderbolt Bus compared to the same number of 5400 rpm HDs on a FW Bus simply because of the extra Bandwidth a TB bus provides for.

gsaudio wrote:

Thanks Guys for your reactions

@Pancenter

The drives are formatted mac os extended journaling on, can you tell me what the difference is?

Journaling keeps track of everything written to the drive and in some cases can be in conflict with the manner in which a hard drive write buffer caches (and reorders) data. Since you're using a raid system I'm unsure how much of an effect journaling is having but my guess is you will get better performance with journaling off.

Journaling is a type of data protection scheme as it makes recovering from a disk error much faster, however... the kicker is it doesn't really work for large audio/graphic/video files but can aid in recovering small files. The general consensus is to format with journaling off on data drives. Apple also mentions this in one of the journaling support articles. Also, make sure spotlight is disabled for those drives. You don't want the #$%%# operating system micro managing the data drives

Shhh... don't tell anyone, I've had journaling off on all my drives for years.. system runs smoother, faster.

gsaudio wrote:

@ Pancenter:

OK, where can i set the journaling off on the disk? do i have to reformat the disk, because the only options i get when i try to do so is mac os extended journaled, mac os extended journaled caps sensitive and exfat. Am i overlooking something?

Not familiar with the later operating systems, snow leopard works well with Logic so I see no need to upgrade.

Try this, open disk utility, select the drive you wish to change, hold down the Option key and mouse up to the disk utility FILE menu, do you see "Disable Journaling"?

I think I would do this on both raid drives and then reboot the Mac.

I see the drives are Seagate, there was a problem with some Seagate drives a while back, may have had to do with power management or tracking geometry, Art of Sound may be able to fill in the blanks, as I recall, the drives were 500GB models, and possibly a few others.

Yes, I can confirm that this particular Seagate model is one of those that has the 'green' 'varipower' functionality and therefore can, under certain circumstances, give poor performance when used for Audio work.. though it is very suitable for other uses such as Time Machine backups or general data storage/backup and retrieval....

If you look under Section 3.9.4 of the PDF you provided a link to above... you will find the info relating to the various Power Saving Modes this drive has... and while it would seem to indicate it only enters these various modes under control by the Host computer, i can assure you this has been found not to be the case as it will self determine certain modes under certain situations, leading to poor Audio (and video for that matter) performance no matter what settings are confgured on the Host Computer...

I'm not saying that it is absolutely the fault of the ext HD, as to why you are having such issues, (because other factors can come into play too like other installed software running in the background as a simple example) but i am saying it is possible and quite likely this is one if not the, reason for such poor performance.

I'd also like to confirm Erik's comments about not using Raid setups for Audio streaming as while they do provide a degree of protection of your data... and would appear to offer higher streaming speeds... the overall performance can take a hit as well and in fact as Erick stated, it is Seek and Access times (taking into account any delays or reduced times caused by Power management software) that are the real factors that matter....

This is in part why I have always used Glyph external HDs because they are hand choosen for high performance in real world Audio/Video applications and while they are a little more expensive that the usual domestic HDs.. they are extremely well built, are well ventilated.. and they come with an excellent warranty that includes data retrieval should the drive fail.. (which they all do at some point I might add!) and of course they do indeed give excellent and stable performance... under a variety of different loads and situations.

To give you an example of a real world performance/situation here.. I am currently working on a project using 10.8.3/9.1.8 64bit... on a 2011 Mac Mini Server that has an i7 2.0Ghz 8GB configuration along with a single Gylph 1TB ext FW800 HD formatted without journalling.. (and the MMS's internal twin 500GB 7200 HDs...) and i am using 34 separate full length stereo audio tracks (recorded live mic'd up Orchestra) at 48khz each stored on the Glyph.. with it's own multiband EQ insert...and several different Reverbs etc... spread across the Auxes..and I am not even pushing my Mac Mini's I/O capabilities hard in any sense...

Hope this helps in some sense...

Additional Note: See the section on Idle & Standby Timers just below the section of the various Power modes in the Seagate PDF for further information on why this particular model of HD can and does go into 'power saving' modes of it's own accord...

Idle and Standby timers

Each time the drive performs an Active function (read, write or seek), the standby timer is reinitialized and begins counting down from its specified delay times to zero. If the standby timer reaches zero before any drive activity is required, the drive makes a transition to Standby mode. In both Idle and Standby mode, the drive accepts all commands and returns to Active mode when disc access is necessary.

The setting for the 'countdown' seems to be very short for these particular models of HD and is apparently not configurable by the User... which leads to the drive 'going to sleep' at every and any opportunity! It is suggested that this setting is set so short to provide better Power saving test results and also less continuous loads/running to help with reliability for such domestic quality drives...