OS 10.12.4 update/Time Machine slowness problem

JohnH17 said:

Many thanks, ManoaHi

I'm still looking for the most appropriate external disk to buy. If you think my iMac HD is nearing the end of its life, is there any merit in having a bootable Ext HD? If so, how do I do this?



When you say clone my internal disk, do you mean make a TM backup of it?

John

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I don't want to recommend any disk. I have had nothing but trouble with Seagate, with WD giving me nothing to worry about with them, yet many others have had the exact opposite situation. A bootable clone is useful in that you can use this as your primary disk, until you have time to take your iMac in for a disk replacement and then you can clone it back. The only thing to remember is to get a disk with a higher capacity than your current 1TB. You'll need to buy cloning software. This form tends to prefer Carbon Copy Cloner (CCC), but that is $40, but for $10 less, you could get SuperDuper (SD). You should also get a 8+GB flash drive and install macOS on it with the cloning software. You then can boot from that flash drive which will make the cloning faster, but a thumb drive is killer slow but I believe you should always have an alternative booting method. I have several Macs and I always clone the disk before I upgrade the major upgrades (like Yosemite to Sierra) and just let TM do the rest. TM is not a clone and generally won't be bootable and it can't take any open files nor any of the system files. I've made all my Macs Solid State Disks (SSD) and clone and replace was "normal", because I needed the speed boost without outright replacement of the entire Mac, I even do the max memory upgrade. This also had the alternative that I could test the drive before swapping them.

Even if you aren't going to replace the disk yourself, I would still recommend a d USB 3 External Enclosure for SATA drives because bare SATA drives tend to be cheaper than new USB external drives and offer some flexibility. Buy CCC or SD and it will take you through creating a clone. There are several options to set, bootable being one of the settings. If you want to see how to replace an internal HDD, check YouTube there are loads of videos on how to do that. It might be worthwhile if you cannot afford long down times. If you are near an Apple store, if you make clear in your Concierge reservation that you want to wait until they have the disk in stock, because due to the age of your iMac, they might not stock them. (not that your Mac is too old, it isn't too old by a long shot it's just that beyond Apple Care or Apple Care +, they don't keep the stock of the parts, they'd have to order the parts. Also, in the Apple store they have other diagnostic software, because if is the disk subsystem, your main logic board may have to be replaced and a new disk won't be any better that it is now. Generally HDDs are suspected first and they are the cause in the vast majority of cases, and more likely for you that it's the disk for you since other than TM, the Mac works for you. For now, get a new disk, even a stand alone and copy your works onto it, every now and then just keep them updated. That way, even if you have to replace your Mac, you wouldn't be dead in the water.

I'm glad that you at least tried to do a backup. I would recommend that you don't use the Admin login for your general work. Create a regular user login and if you're willing to go through it, child protection which can help keep odd things out. On all my machines, regardless of OS, I only use regular user accounts and login as admin when only absolutely necessary.

John, you said

My iMac isn’t slow with anything else except TM. It has 251GB of Flash Storage and is very speedy.

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That Flash Storage is the internal drive for your mac, and is probably NOT the source of any slowness. Flash storage generally gives little to no warning of failure. The description of what causes slowness that I gave does NOT apply to Flash Storage. So if you are correct that you have flash storage, the internal drive is probably not the problem. I think part of the confusion in this thread is that some of the posts assumed the problem was the internal drive slowing down. But from your descriptions, it sounds like the external is the one that is having the issues.

What I would do is just get a new external drive, with a fast interface and preferably mains power, as I said, and just start a new set of TM backups. Once that is established, you can decide what to do with the current drive--either erase and reformat for storage, or work at getting the historical backups off of it. (The reason for the mains power is primarily that drives draw a LOT of power from the USB port, that's all. I prefer not to tax the internal power source for the USB ports so that they work for the less demanding devices I want to use.)

Apologies for any confusion I have caused.

I think Jake is right about the iMac HD with 251GB of Flash Storage being OK. I only bought the iMac (new) in June 2015. To repeat, I don’t have a problem accessing the historical backups from the WD Ext HD Time Machine backups.

I’m sorry I can’t upload a Screen Grab (.tiff) of the backups.backupdb folder. It shows, e.g., that one backup yesterday was created at 20:56 and modified at 21:12, which seems right for an incremental backup. But Time Machine Preferences yesterday showed it was still backing up when I shut down the iMac at 22:40. Very curious.

I’m out of my depth with most of the things ManoaHi says. I don’t have cloning software to boot the Mac. But this morning, as an experiment, I started my iMac with the Alt key depressed. It gave me three options. Instead of using the default of the iMac HD I selected the Backup Ext HD. It booted up fine. The only thing I had to do was to rejoin my WiFi Network.

I’m still trying to find a suitable Ext HD to follow Jake’s advice. They all seem to be USB 3.0. My existing WD Ext HD is connected via a Thunderbolt adapter to a Firewire 800 port, which I had thought was much faster than USB. Any suggestions of specific models would be greatly appreciated.

John

USB3 is faster than FW800. Firewire is older technology and not very popular at this time, USB3 is relatively new and pretty wide-spread.

Any of these should do. Get what you need for size. https://eshop.macsales.com/shop/external-storage

Amazon has some suitable drives, as do other online stores. Basically, if you have a USB 3 port on that Thunderbolt adapter, any of the USB3 drives should work. But for Firewire, OWC (The link above) may well be the best source.

Many thanks, Jake. I live in the UK and so I'll see if the OWC products are available here.

Apologies for dumb question. My Thunderbolt is Thunderbolt to Firewire adapter; I'm pretty sure it doesn't have a USB3 connection. However, I do have a cable that fits into one of my iMac USB ports at one end and the other end is USB3. Will this connect my iMac with a USB3 Ext HD?

I've re-checked my iMac specs. Yes, it does have 256GB of flash storage, but this was an extra, in addition to 1TB hard drive storage. I was told this extra would speed up the iMac. Does this info affect what you said about my iMac not being responsible for the curious behaviour of Time Machine?

John

John, I think it best that you take the machine to an Apple store for them to test. You have kept adding factors to the problem that are making this thread extremely hard to follow and for us (me) to keep it all straight. Adding now that you DO have an internal spinner drive adds a layer of complication that had, up to then, not been considered. It is entirely possible that all of your drives are fine, or that all of them are failing. You say you can see the backups in TM, but then that it takes hours to do a new backup, a set of statements that is inconsistent and difficult to understand, unless there is yet another factor not being mentioned.

So, my honest best advice is to take the iMac and the ext hd to an Apple store for testing.

Apologies if I’ve caused confusion, Jake. My iMac is less than 2 years old. I didn’t say that it takes hours to do a new backup: it’s more nuanced than that. What I reported was

I’m sorry I can’t upload a Screen Grab (.tiff) of the backups.backupdb folder. It shows, e.g., that one backup yesterday was created at 20:56 and modified at 21:12, which seems right for an incremental backup. But Time Machine Preferences yesterday showed it was still backing up when I shut down the iMac at 22:40. Very curious.

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That is, the incremental backup appears to have taken 16 minutes, but TM preferences at the time show much longer. This is symptomatic of the problem. It IS inconsistent. Today's automatic backup began at 10:11 and is still showing as in progress at 17:44, preventing any other incremental backups. But tomorrow the Backups.backupdb will show that it took a matter of minutes.

The nearest Apple Store is in central London. I don’t have a car, and even if did there is no parking. To lug the iMac there would be time-consuming and no fun. I think it makes more sense to buy another Ext HD and see if TM works on that before going to the Apple store.

John

Understand. I cannot imagine lugging the iMac on the Tube or busses through London! Once you have a good backup, you can try reinstalling and formatting the drive you plan to install to, then doing a restore from the backup.

The challenge is, of course, you have TWO drives internally. If they are fused, they will look like one drive, but if not, you will have two drives separately showing, and you will have to be careful to install the OS to the proper one, the one you are booting from (probably the Flash Drive).

Just thought this might be a good time to suggest using either CCC (Carbon Copy Cloner) or SD! (SuperDuper!) for a bootable clone backup rather than Time Machine.

Just saying…




Patrick
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Thanks, Jake. The iMac drive only ever appears as Macintosh HD in the LH column of the Finder window, so I suppose the 256GB of flash storage is “fused” to the 1TB hard drive storage (whatever fused means). When I bought it, I just opted for the flash storage as a customisable extra because the Apple sales person said it would speed up the iMac.

Do you still think I need to reinstall and format the Macintosh HD? As I said, it’s less than 2 years old.

Thanks, Patrick, for your suggestion. CCC and SD! seem v complex for a non-techie like me. I still don’t know the difference between a bootable clone and a TM backup.

John

Thanks, Patrick, for your suggestion. CCC and SD! seem v complex for a non-techie like me. I still don’t know the difference between a bootable clone and a TM backup.

Click to expand...

Both CCC and SD are pretty simple John, you select the source and then the target volume with the option to backup everything and then click the Clone button and/or setup and save a schedule if you want.

A bootable backup clone can be used to boot the Mac, a TM backup cannot.




- Patrick
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Actually, Patrick, TM backups can be booted, if you are on a more modern Mac. I don't know when Apple started allowing it, but if you can do an EFI boot, then you can boot the TM drive that way.

To reinforce what Jake stated about Time Machine backups being bootable... the following excerpt taken from the Apple KB article: "Use Time Machine to back up or restore your Mac"

In OS X Lion v10.7.3 or later, you can also start up from your Time Machine disk, if necessary. Hold down the Option key as your Mac starts up. When you see the Startup Manager screen, choose “EFI Boot” as the startup disk.

Apparently EFI boot using Time Machine became available from Lion 10.7.3 on. And by the way, I tested this myself using my latest Time Machine backup and Sierra. It does work.

Patrick, I said earlier today

I don’t have cloning software to boot the Mac. But this morning, as an experiment, I started my iMac with the Alt key depressed. It gave me three options. Instead of using the default of the iMac HD I selected the Backup Ext HD. It booted up fine. The only thing I had to do was to rejoin my WiFi Network.

Click to expand...

Since TM backs up to this Ext HD, does this confirm what Jake and chscag say above?

John

Thanks Jake and chscag , I keep forgetting that a BOOTABLE TM backup may be possible.

And John, maybe just try testing your TM backup as suggested and see if it works for you as a bootable volume.





- Patrick
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Patrick, I thought I had tested it as a bootable volume

Patrick, I said earlier today
I don’t have cloning software to boot the Mac. But this morning, as an experiment, I started my iMac with the Alt key depressed. It gave me three options. Instead of using the default of the iMac HD I selected the Backup Ext HD. It booted up fine. The only thing I had to do was to rejoin my WiFi Network.

Click to expand...

Jake, I think the confusion I caused you by saying that my iMac also has 1TB of HD storage is incorect. I thought that when the Apple sales person said the 250GB of Flash storage was £160 extra to the cost of a 1TB HD iMac, then this was additional storage. However, when I get Info on Macintosh HD is says "Capacity 250.14GB; Available 86.99GB; Used 163.15GB on disk"

And the About this Mac>System Report> Storage says "Macintosh HD Capacity 250.14 GB"

Am I right in thinking that it doesn't have 1TB of HD storage?

John

Given what you said, yes, it looks like that is all the storage you have. And flash storage is unlikely to fail slowly. It either works or doesn't.