Time machine backups very, very slow

Actually, the "deep event scan" finished after 5 Minutes, but the backup is still "preparing". Hence, the deep event scan is unlikely that it's the cause of the slow backup. Activity Monitor tells me that a "kernel task" is constantly active, and it seems that it is talking to the network share, sending tons of small packets back and forth. No idea what is causing this. The logs now say "com.apple.backupd: not using file event preflight for Machintosh HD", which sounds like a bad thing.

Anyone knows what triggers this, and how it can be prevented?

EDIT: Thanks for the hint with pondini.org, that looks like very useful information. I'll browse through and see whether I can find any hints to what might be going wrong.

Huitzilo. wrote:

EDIT: Thanks for the hint with pondini.org, that looks like very useful information. I'll browse through and see whether I can find any hints to what might be going wrong.

Keep in mind that pondini.org is the web site of now deceased ASC member Pondini. The site has not been updated since his death two years ago, so some of the info on it may be somewhat out of date with respect to OS X versions released since that time. Also, the site may or may not expire soon, depending on what his son wants to do about that (more info about that in Pondini's Time Machine) so don't wait too long to check out this excellent resource for all things related to Time Machine.

Count me in as another who has extremely slow backups since El Capitan. My backups are either to a Time Capsule over WiFi (i.e. all Apple products); or via UBS3 cable to a Western Digital external drive with plenty of unused capacity. My wife's computer is also experiencing same issue.

Huitzilo. wrote:

Actually, the "deep event scan" finished after 5 Minutes, but the backup is still "preparing". Hence, the deep event scan is unlikely that it's the cause of the slow backup. Activity Monitor tells me that a "kernel task" is constantly active, and it seems that it is talking to the network share, sending tons of small packets back and forth. No idea what is causing this. The logs now say "com.apple.backupd: not using file event preflight for Machintosh HD", which sounds like a bad thing.

If you mean the TM backups to the NAS, then you are likely just seeing the effects of using an unsupported backup device with an OS X version Apple (& probably the NAS maker) never tested it with.

WSE1951 wrote:

Count me in as another who has extremely slow backups since El Capitan. My backups are either to a Time Capsule over WiFi (i.e. all Apple products); or via UBS3 cable to a Western Digital external drive with plenty of unused capacity. My wife's computer is also experiencing same issue.

For the USB 3 drive, you might try running Disk Utility's First Aid on it to make sure there are no file system issues with it. For the Time Capsule, you can do what is basically the same thing by powering it down, waiting a few seconds & then powering it back up. (Every time a Time Capsule starts up it runs an integrity check on its internal HD.)

Also, for the TC you might want to make sure you have no WiFi problems that would slow down the backups. The simplest way to do that is, if practical, run a temporary connection to it using an ethernet cable. Also make sure no other devices are accessing it when you do that test, since other devices on the network could be using some of the available network bandwidth.

I am running Software OS X 10.9.5 (13F1112) . This is Yosemite and not El Capitan. I usually use Time Machine backup once every couple of days using External USB drive that is plugged directly into my iMac. Everything was fine up until 4 days ago. Since yesterday the backup does not seem to work at all. The message I am getting (for example) is "Backing up 641 bytes of 745.3 MB; Calculating time remaining..." and it stays in this position for at least 4 hours. I have 2 separate USB drives that I use for backup. Both the drives are acting like this for the past 2 days.

I too am suffering terribly slow Time Machine backups since upgrading to El Capitan on my iMac. I have 2 Time Machine targets:

1) Apple Time Capsule directly attached with Ethernet

2) Netgear RadyNAS ethernet attached to the Time Capsule

(I'm well aware of the limitations of Time Machine with some NAS implementations but it's been working for years with my ReadyNAS's AFP implementation once they added support and I've even performed successful restores -- but your milage may vary)

Since upgrading to El Capitan my backups have become very very slow and haven't actually completed in the past 10 days due to energy saver sleeps. I started a fresh backup to the NAS that didn't complete in days and I've now restarted that but in the past 5 hours since the actual backup started (prepare finished) it's only backed up 471MB ⚠ which is an astoundingly slow rate of 27 KB/sec (seems to have really slowed down in the last hour)

11/18/15 7:33:58.860 AM com.apple.backupd[1022]: 453.77 GB required (including padding), 542.11 GB available

11/18/15 8:34:11.314 AM com.apple.backupd[1022]: Copied 31.9 MB of 432.3 GB, 27703 of 4387514 items

11/18/15 9:34:15.726 AM com.apple.backupd[1022]: Copied 371.6 MB of 432.3 GB, 45124 of 4387514 items

11/18/15 10:34:20.332 AM com.apple.backupd[1022]: Copied 375 MB of 432.3 GB, 68045 of 4387514 items

11/18/15 11:34:20.784 AM com.apple.backupd[1022]: Copied 471.1 MB of 432.3 GB, 91576 of 4387514 items

11/18/15 12:34:23.067 PM com.apple.backupd[1022]: Copied 471.6 MB of 432.3 GB, 130400 of 4387514 items

My MacBook running Mavericks is still backing up fine and fast to both of these same Time Machine targets.

Something seems really broken with El Capitan Time Machine backups.

Gaijin Kuma wrote:

Something seems really broken with El Capitan Time Machine backups.

Just FYI, one of my two Time Machine targets is a Time Capsule connected to my iMac via a gigabit ethernet connection (the other is a USB 3 drive connected directly to the iMac), & my El Capitan TM backups are very fast, maybe even slightly faster than they were with Mavericks or Yosemite.

Your ReadyNAS attached to the TC may be part of your problem -- regardless of how well it worked with older OS versions, it is not supported by Apple & there is no guarantee that it will do so with El Cap or any future version. I suggest contacting Netgear or searching the web for any info about them adding support for El Cap to their NAS, but keep in mind Apple has nothing to do with this.

Accordingly, as a test you might try taking the NAS offline & seeing if that makes any difference.

Regardless of that, note this line from your log (emphasis added):

11/18/15 8:34:11.314 AM com.apple.backupd[1022]: Copied 31.9 MB of 432.3 GB, 27703 of 4387514 items

That is a very large backup size & a very large number of items, indicative of TM trying to do a full backup of the backed up drive rather than an incremental one. Even if it is just doing a check & won't really add all those 4 million plus items to the TM backup, it can take many hours to work its way through them all.

IOW, a TM backup doesn't ever just copy files at the fastest possible rate allowed by the connection because there is a lot of overhead involved in checking the existing backups, the hard links, & so on.

I'm on a MB running 10.1.1 connected to the latest model Time Capsule. It hasn't backed up in over 30 days. The MB has been connected to the network nonstop for a week and I'm currently at 3.7MB of 189.9GB. The TC has 1.6 TB available. As much as all this cost to "just work", it doesn't and I'm ******.

R C-R wrote:

Your ReadyNAS attached to the TC may be part of your problem

Nope, it's just using one of the ethernet ports on the TC. There isn't any magic happening with that connection, it's just an Ethernet connection. Other traffic to the ReadyNAS and Time Capsule is working as fast as expected.

If I only saw the issue on the ReadyNAS I might agree but I'm having the same slow issue backing up to the Time Capsule too. An incremental backup to the Time Capsule of ~4GB had been running for a couple days when I decided to try rebooting the iMac and started the fresh backup show in my original post.

I've also looked at the SMART status of the Fusion drive in my iMac and don't see any errors or troubled counters from the HDD or SSD.

Maybe the Fusion drive setup is related to the issue ? Does everyone experiencing the issue have the Fusion drive in the Mac ?

R C-R wrote:

That is a very large backup size & a very large number of items, indicative of TM trying to do a full backup of the backed up drive rather than an incremental one. Even if it is just doing a check & won't really add all those 4 million plus items to the TM backup, it can take many hours to work its way through them all.

IOW, a TM backup doesn't ever just copy files at the fastest possible rate allowed by the connection because there is a lot of overhead involved in checking the existing backups, the hard links, & so on.

Yeah, I'm pretty familiar with storage and know that there is a lot of metadata processing overhead with so many small files and in the past typically see the throughput vary between several hundred KB/sec to a few MB/sec depending on the size of the files being processed. I taken several fresh backups so I know what to expect and this simply isn't working properly. Glad you aren't having issue but it seems several other people really are so please don't discount it all immediately.

Latest status on my full backup is less than 1TB in the last day, so it seems it's going to take more than a year to complete my backup. Time to open a ticket with Apple.

11/19/15 6:13:30.993 AM com.apple.backupd[1022]: Copied 982.6 MB of 432.3 GB, 741976 of 4387514 items

Gaijin Kuma wrote:

Your ReadyNAS attached to the TC may be part of your problem

Nope, it's just using one of the ethernet ports on the TC. There isn't any magic happening with that connection, it's just an Ethernet connection.

Actually, there is a great deal of "magic" involved in getting a NAS to support Time Machine. See for example my comments in Can I use TM with NAS? about all the "under the hood" stuff that a NAS has to do to support Time Machine. It requires much more than just an ethernet connection -- the NAS is a computer running its own operating system, & like any other computer on a network, it must support all the appropriate network protocols & OS X file system features to be compatible with a Mac running OS X & trading files with it.

R C-R wrote:

Gaijin Kuma wrote:

Your ReadyNAS attached to the TC may be part of your problem

Nope, it's just using one of the ethernet ports on the TC. There isn't any magic happening with that connection, it's just an Ethernet connection.

Actually, there is a great deal of "magic" involved in getting a NAS to support Time Machine. See for example my comments in Can I use TM with NAS? about all the "under the hood" stuff that a NAS has to do to support Time Machine. It requires much more than just an ethernet connection -- the NAS is a computer running its own operating system, & like any other computer on a network, it must support all the appropriate network protocols & OS X file system features to be compatible with a Mac running OS X & trading files with it.

Yes, I work with large NAS systems every day and know how they work but having the NAS plugged into the Time Capsule ethernet port isn't affecting the backup direct to the Time Capsule as you implied earlier. Maybe that's not what you meant.

I also have a USB drive I backup to quarterly so I may try hooking that up but based on some other replies is sounds like they are having slowness with USB attached drives as well.

Delete from the root of the Mac or NAS?

Just adding my similar complaint to the pile. I have this problem, except that I don't use Time Machine over a network. I'm not sure the issues re: "networked" devices have anything to do with this. I use a Western Digital drive connected via USB, and all was fine until I upgraded to El Capitan. Now it takes all day to back up maybe a tenth of my drive. It will literally be working for many days and nights to back up the whole thing, whereas before it took only a few hours. I've tried excluding other users from the backup, and I've tried reformatting the backup disk, even though I know that means I will need to backup from scratch. It's not stuck on "preparing." It's actually transferring data, but the speed is ridiculously slow. Hoping someone will post a simple fix. Or any fix.

Same issue here since El Capitan my Time Machine back up over wifi to an external NAS Synology has been sluggish, it takes hours to back up few MBs of data!!!! I have sent feedbacks to Apple as this process is clearly broken. Before with Yosemite it would take minutes at most.